diff --git a/src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs b/src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs
index edd51b148cf0ff..d41e07217ee335 100644
--- a/src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs
+++ b/src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs
@@ -711,6 +711,7 @@ public abstract class StandaloneStreamConformanceTests : StreamConformanceTests
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ArgumentValidation_ThrowsExpectedException()
         {
             await foreach (Stream? stream in GetStreamsForValidation())
@@ -724,6 +725,7 @@ public virtual async Task ArgumentValidation_ThrowsExpectedException()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Disposed_ThrowsObjectDisposedException()
         {
             await foreach (Stream? stream in GetStreamsForValidation())
@@ -813,6 +815,7 @@ public virtual async Task Read_DataStoredAtDesiredOffset(ReadWriteMode mode)
         [InlineData(ReadWriteMode.SyncArray)]
         [InlineData(ReadWriteMode.AsyncArray)]
         [InlineData(ReadWriteMode.AsyncAPM)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Write_DataReadFromDesiredOffset(ReadWriteMode mode)
         {
             using Stream? stream = await CreateReadWriteStream();
@@ -1601,6 +1604,7 @@ protected static bool Bidirectional(StreamPair streams) =>
             streams.Stream2.CanRead && streams.Stream2.CanWrite;
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ArgumentValidation_ThrowsExpectedException()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1612,6 +1616,7 @@ public virtual async Task ArgumentValidation_ThrowsExpectedException()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Disposed_ThrowsObjectDisposedException()
         {
             StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1624,6 +1629,7 @@ public virtual async Task Disposed_ThrowsObjectDisposedException()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadWriteAsync_PrecanceledOperations_ThrowsCancellationException()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1635,6 +1641,7 @@ public virtual async Task ReadWriteAsync_PrecanceledOperations_ThrowsCancellatio
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadAsync_CancelPendingTask_ThrowsCancellationException()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1644,6 +1651,7 @@ public virtual async Task ReadAsync_CancelPendingTask_ThrowsCancellationExceptio
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadAsync_CancelPendingValueTask_ThrowsCancellationException()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1653,6 +1661,7 @@ public virtual async Task ReadAsync_CancelPendingValueTask_ThrowsCancellationExc
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadWriteByte_Success()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1721,6 +1730,7 @@ public virtual async Task ReadWrite_Success_Large(ReadWriteMode mode, int writeS
 
         [Theory]
         [MemberData(nameof(ReadWrite_Success_MemberData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadWrite_Success(ReadWriteMode mode, int writeSize, bool startWithFlush)
         {
             foreach (CancellationToken nonCanceledToken in new[] { CancellationToken.None, new CancellationTokenSource().Token })
@@ -1778,6 +1788,7 @@ public virtual async Task ReadWrite_Success(ReadWriteMode mode, int writeSize, b
         [Theory]
         [MemberData(nameof(AllReadWriteModesAndValue), false)]
         [MemberData(nameof(AllReadWriteModesAndValue), true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Read_Eof_Returns0(ReadWriteMode mode, bool dataAvailableFirst)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1816,6 +1827,7 @@ public virtual async Task Read_Eof_Returns0(ReadWriteMode mode, bool dataAvailab
         [InlineData(ReadWriteMode.SyncArray)]
         [InlineData(ReadWriteMode.AsyncArray)]
         [InlineData(ReadWriteMode.AsyncAPM)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Read_DataStoredAtDesiredOffset(ReadWriteMode mode)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1845,6 +1857,7 @@ public virtual async Task Read_DataStoredAtDesiredOffset(ReadWriteMode mode)
         [InlineData(ReadWriteMode.SyncArray)]
         [InlineData(ReadWriteMode.AsyncArray)]
         [InlineData(ReadWriteMode.AsyncAPM)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Write_DataReadFromDesiredOffset(ReadWriteMode mode)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -1943,6 +1956,7 @@ public static IEnumerable<object[]> ReadAsync_ContinuesOnCurrentContextIfDesired
 
         [Theory]
         [MemberData(nameof(ReadAsync_ContinuesOnCurrentContextIfDesired_MemberData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadAsync_ContinuesOnCurrentSynchronizationContextIfDesired(bool flowExecutionContext, bool? continueOnCapturedContext)
         {
             await default(JumpToThreadPoolAwaiter); // escape xunit sync ctx
@@ -2025,6 +2039,7 @@ public virtual async Task ReadAsync_ContinuesOnCurrentSynchronizationContextIfDe
 
         [Theory]
         [MemberData(nameof(ReadAsync_ContinuesOnCurrentContextIfDesired_MemberData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadAsync_ContinuesOnCurrentTaskSchedulerIfDesired(bool flowExecutionContext, bool? continueOnCapturedContext)
         {
             await default(JumpToThreadPoolAwaiter); // escape xunit sync ctx
@@ -2114,6 +2129,7 @@ await Task.Factory.StartNew(() =>
         [InlineData(ReadWriteMode.AsyncMemory)]
         [InlineData(ReadWriteMode.SyncAPM)]
         [InlineData(ReadWriteMode.AsyncAPM)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ZeroByteRead_BlocksUntilDataAvailableOrNops(ReadWriteMode mode)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2176,6 +2192,7 @@ public virtual async Task ZeroByteRead_BlocksUntilDataAvailableOrNops(ReadWriteM
         [InlineData(ReadWriteMode.AsyncMemory)]
         [InlineData(ReadWriteMode.SyncAPM)]
         [InlineData(ReadWriteMode.AsyncAPM)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ZeroByteWrite_OtherDataReceivedSuccessfully(ReadWriteMode mode)
         {
             byte[][] buffers = new[] { Array.Empty<byte>(), Encoding.UTF8.GetBytes("hello"), Array.Empty<byte>(), Encoding.UTF8.GetBytes("world") };
@@ -2229,6 +2246,7 @@ public virtual async Task ZeroByteWrite_OtherDataReceivedSuccessfully(ReadWriteM
         [Theory]
         [InlineData(false)]
         [InlineData(true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadWrite_CustomMemoryManager_Success(bool useAsync)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2349,6 +2367,7 @@ public virtual async Task CopyToAsync_AllDataCopied_Large(bool useAsync) =>
 
         [Theory]
         [MemberData(nameof(CopyToAsync_AllDataCopied_MemberData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task CopyToAsync_AllDataCopied(int byteCount, bool useAsync)
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2386,6 +2405,7 @@ await Task.WhenAll(Enumerable.Range(0, 20).Select(_ => Task.Run(async () =>
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Timeout_Roundtrips()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2420,6 +2440,7 @@ public virtual async Task Timeout_Roundtrips()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task ReadTimeout_Expires_Throws()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2554,6 +2575,7 @@ public virtual async Task ReadAsync_DuringReadAsync_ThrowsIfUnsupported()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Flush_ValidOnWriteableStreamWithNoData_Success()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2568,6 +2590,7 @@ public virtual async Task Flush_ValidOnWriteableStreamWithNoData_Success()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Flush_ValidOnReadableStream_Success()
         {
             using StreamPair streams = await CreateConnectedStreamsAsync();
@@ -2585,6 +2608,7 @@ public virtual async Task Flush_ValidOnReadableStream_Success()
         [InlineData(0)]
         [InlineData(1)]
         [InlineData(2)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Dispose_ClosesStream(int disposeMode)
         {
             if (!CansReturnFalseAfterDispose)
diff --git a/src/libraries/Common/tests/System/IO/Compression/CompressionStreamUnitTestBase.cs b/src/libraries/Common/tests/System/IO/Compression/CompressionStreamUnitTestBase.cs
index 2935ef6fd3f829..407d1ee24d7396 100644
--- a/src/libraries/Common/tests/System/IO/Compression/CompressionStreamUnitTestBase.cs
+++ b/src/libraries/Common/tests/System/IO/Compression/CompressionStreamUnitTestBase.cs
@@ -48,6 +48,7 @@ public virtual void FlushAsync_DuringWriteAsync()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task FlushAsync_DuringReadAsync()
         {
             byte[] buffer = new byte[32];
@@ -76,6 +77,7 @@ public async Task FlushAsync_DuringReadAsync()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task FlushAsync_DuringFlushAsync()
         {
             byte[] buffer = null;
@@ -118,6 +120,7 @@ public async Task FlushAsync_DuringFlushAsync()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public virtual async Task Dispose_WithUnfinishedReadAsync()
         {
             string compressedPath = CompressedTestFile(UncompressedTestFile());
@@ -137,6 +140,7 @@ public virtual async Task Dispose_WithUnfinishedReadAsync()
         [Theory]
         [MemberData(nameof(UncompressedTestFiles))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Read(string testFile)
         {
             var uncompressedStream = await LocalMemoryStream.readAppFileAsync(testFile);
@@ -173,6 +177,7 @@ public async Task Read(string testFile)
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Read_EndOfStreamPosition()
         {
             var compressedStream = await LocalMemoryStream.readAppFileAsync(CompressedTestFile(UncompressedTestFile()));
@@ -193,6 +198,7 @@ public async Task Read_EndOfStreamPosition()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Read_BaseStreamSlowly()
         {
             string testFile = UncompressedTestFile();
@@ -328,6 +334,7 @@ IEnumerable<Func<Stream, Stream>> CtorFunctions()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task TestLeaveOpenAfterValidDecompress()
         {
             //Create the Stream
@@ -403,6 +410,7 @@ public void BaseStreamTest(CompressionMode mode)
         [InlineData(CompressionMode.Compress)]
         [InlineData(CompressionMode.Decompress)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task BaseStream_Modify(CompressionMode mode)
         {
             using (var baseStream = await LocalMemoryStream.readAppFileAsync(CompressedTestFile(UncompressedTestFile())))
@@ -435,6 +443,7 @@ public void BaseStream_NullAfterDisposeWithFalseLeaveOpen(CompressionMode mode)
         [InlineData(CompressionMode.Compress)]
         [InlineData(CompressionMode.Decompress)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36845", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task BaseStream_ValidAfterDisposeWithTrueLeaveOpen(CompressionMode mode)
         {
             var ms = await LocalMemoryStream.readAppFileAsync(CompressedTestFile(UncompressedTestFile()));
@@ -453,6 +462,7 @@ public async Task BaseStream_ValidAfterDisposeWithTrueLeaveOpen(CompressionMode
 
         [Theory]
         [MemberData(nameof(UncompressedTestFiles))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task CompressionLevel_SizeInOrder(string testFile)
         {
             using var uncompressedStream = await LocalMemoryStream.readAppFileAsync(testFile);
diff --git a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDsa/ECDsaTests.netcoreapp.cs b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDsa/ECDsaTests.netcoreapp.cs
index ab36bacd98d4eb..e2040d47888d3d 100644
--- a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDsa/ECDsaTests.netcoreapp.cs
+++ b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDsa/ECDsaTests.netcoreapp.cs
@@ -80,6 +80,7 @@ public void KeySizeProp()
         }
 
         [Theory, MemberData(nameof(TestNewCurves))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TestRegenKeyExplicit(CurveDef curveDef)
         {
             ECParameters param, param2;
diff --git a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
index 96d9b51372847f..80fbbace5b58a9 100644
--- a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
+++ b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
@@ -338,6 +338,7 @@ private void RsaCryptRoundtrip(RSAEncryptionPadding paddingMode, bool expectSucc
 
         [Fact]
         [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52199", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RoundtripEmptyArray()
         {
             using (RSA rsa = RSAFactory.Create(TestData.RSA2048Params))
diff --git a/src/libraries/Common/tests/Tests/System/StringTests.cs b/src/libraries/Common/tests/Tests/System/StringTests.cs
index fcee8ec7d78cce..b3ab3defdb967d 100644
--- a/src/libraries/Common/tests/Tests/System/StringTests.cs
+++ b/src/libraries/Common/tests/Tests/System/StringTests.cs
@@ -7300,6 +7300,7 @@ public static void InternalTestAotSubset()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotInvariantGlobalization))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34577", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static unsafe void NormalizationTest() // basic test; more tests in globalization tests
         {
             // U+0063  LATIN SMALL LETTER C
diff --git a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostBuilderTests.cs b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostBuilderTests.cs
index 6bd8eb91826389..a07be287a3b95d 100644
--- a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostBuilderTests.cs
+++ b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostBuilderTests.cs
@@ -277,6 +277,7 @@ public void HostConfigParametersReadCorrectly()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RelativeContentRootIsResolved()
         {
             using (var host = new HostBuilder()
diff --git a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostTests.cs b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostTests.cs
index 7fe9ceca422bb2..fe0a4145fe3d27 100644
--- a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostTests.cs
+++ b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/HostTests.cs
@@ -21,6 +21,7 @@ namespace Microsoft.Extensions.Hosting.Tests
     public partial class HostTests
     {
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public async Task StopAsyncWithCancellation()
         {
             var builder = new HostBuilder();
diff --git a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/Internal/HostTests.cs b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/Internal/HostTests.cs
index dd8e96507f3bba..989ea8c1caf46f 100644
--- a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/Internal/HostTests.cs
+++ b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/Internal/HostTests.cs
@@ -19,6 +19,7 @@
 
 namespace Microsoft.Extensions.Hosting.Internal
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public class HostTests
     {
         [Fact]
diff --git a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/OptionsBuilderExtensionsTests.cs b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/OptionsBuilderExtensionsTests.cs
index ddcce5ce2c47b4..5155fa46fa9ef4 100644
--- a/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/OptionsBuilderExtensionsTests.cs
+++ b/src/libraries/Microsoft.Extensions.Hosting/tests/UnitTests/OptionsBuilderExtensionsTests.cs
@@ -26,6 +26,7 @@ public void ValidateOnStart_NullOptionsBuilder_Throws()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_ConfigureAndValidateThenCallValidateOnStart_ValidatesFailure()
         {
             var hostBuilder = CreateHostBuilder(services =>
@@ -49,6 +50,7 @@ public async Task ValidateOnStart_ConfigureAndValidateThenCallValidateOnStart_Va
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_CallFirstThenConfigureAndValidate_ValidatesFailure()
         {
             var hostBuilder = CreateHostBuilder(services =>
@@ -72,6 +74,7 @@ public async Task ValidateOnStart_CallFirstThenConfigureAndValidate_ValidatesFai
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_ErrorMessageSpecified_FailsWithCustomError()
         {
             var hostBuilder = CreateHostBuilder(services =>
@@ -102,6 +105,7 @@ internal class FakeSettings
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_NamedOptions_ValidatesFailureOnStart()
         {
             var hostBuilder = CreateHostBuilder(services =>
@@ -130,6 +134,7 @@ public async Task ValidateOnStart_NamedOptions_ValidatesFailureOnStart()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         private async Task ValidateOnStart_AddOptionsMultipleTimesForSameType_LastOneGetsTriggered()
         {
             bool firstOptionsBuilderTriggered = false;
@@ -176,6 +181,7 @@ private async Task ValidateOnStart_AddOptionsMultipleTimesForSameType_LastOneGet
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         private async Task ValidateOnStart_AddEagerValidation_DoesValidationWhenHostStartsWithNoFailure()
         {
             bool validateCalled = false;
@@ -203,6 +209,7 @@ private async Task ValidateOnStart_AddEagerValidation_DoesValidationWhenHostStar
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         private async Task ValidateOnStart_AddLazyValidation_SkipsValidationWhenHostStarts()
         {
             bool validateCalled = false;
@@ -236,6 +243,7 @@ private async Task ValidateOnStart_AddLazyValidation_SkipsValidationWhenHostStar
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_AddBothLazyAndEagerValidationOnDifferentTypes_ValidatesWhenHostStartsOnlyForEagerValidations()
         {
             bool validateCalledForNested = false;
@@ -279,6 +287,7 @@ public async Task ValidateOnStart_AddBothLazyAndEagerValidationOnDifferentTypes_
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_MultipleErrorsInOneValidationCall_ValidatesFailureWithMultipleErrors()
         {
             var hostBuilder = CreateHostBuilder(services =>
@@ -307,6 +316,7 @@ public async Task ValidateOnStart_MultipleErrorsInOneValidationCall_ValidatesFai
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34582", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52114", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ValidateOnStart_MultipleErrorsInOneValidationCallUsingCustomErrors_FailuresContainCustomErrors()
         {
             var hostBuilder = CreateHostBuilder(services =>
diff --git a/src/libraries/Microsoft.Extensions.Logging.Console/tests/Microsoft.Extensions.Logging.Console.Tests/SimpleConsoleFormatterTests.cs b/src/libraries/Microsoft.Extensions.Logging.Console/tests/Microsoft.Extensions.Logging.Console.Tests/SimpleConsoleFormatterTests.cs
index cef2eafb73014e..46c88511870324 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Console/tests/Microsoft.Extensions.Logging.Console.Tests/SimpleConsoleFormatterTests.cs
+++ b/src/libraries/Microsoft.Extensions.Logging.Console/tests/Microsoft.Extensions.Logging.Console.Tests/SimpleConsoleFormatterTests.cs
@@ -14,6 +14,7 @@ public class SimpleConsoleFormatterTests : ConsoleFormatterTests
         [InlineData(LoggerColorBehavior.Enabled)]
         [InlineData(LoggerColorBehavior.Disabled)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50575", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51398", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Log_WritingScopes_LogsWithCorrectColorsWhenColorEnabled(LoggerColorBehavior colorBehavior)
         {
             // Arrange
diff --git a/src/libraries/Microsoft.VisualBasic.Core/tests/InteractionTests.cs b/src/libraries/Microsoft.VisualBasic.Core/tests/InteractionTests.cs
index 285740ece2ffdf..962749c6a6e8a2 100644
--- a/src/libraries/Microsoft.VisualBasic.Core/tests/InteractionTests.cs
+++ b/src/libraries/Microsoft.VisualBasic.Core/tests/InteractionTests.cs
@@ -104,6 +104,7 @@ public void Choose()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50572", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Command()
         {
             var expected = Environment.CommandLine;
diff --git a/src/libraries/Microsoft.VisualBasic.Core/tests/Microsoft/VisualBasic/FileIO/FileSystemTests.cs b/src/libraries/Microsoft.VisualBasic.Core/tests/Microsoft/VisualBasic/FileIO/FileSystemTests.cs
index 91a74b165e1488..6c8ee593729cf2 100644
--- a/src/libraries/Microsoft.VisualBasic.Core/tests/Microsoft/VisualBasic/FileIO/FileSystemTests.cs
+++ b/src/libraries/Microsoft.VisualBasic.Core/tests/Microsoft/VisualBasic/FileIO/FileSystemTests.cs
@@ -180,6 +180,7 @@ public void CopyFile_FileSourceFileName_DestinationFileName()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void CopyFile_FileSourceFileName_DestinationFileName_OverwriteFalse()
         {
             var testFileSource = GetTestFilePath();
@@ -734,6 +735,7 @@ public void MoveFile_SourceFileName_DestinationFileName()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void MoveFile_SourceFileName_DestinationFileName_OverwriteFalse()
         {
             var SourceFileNameWithPath = CreateTestFile(SourceData, TestFileName: GetTestFileName());
diff --git a/src/libraries/System.Collections.Immutable/tests/ImmutableArrayTest.cs b/src/libraries/System.Collections.Immutable/tests/ImmutableArrayTest.cs
index 490373ed9ba953..c43195713fdf63 100644
--- a/src/libraries/System.Collections.Immutable/tests/ImmutableArrayTest.cs
+++ b/src/libraries/System.Collections.Immutable/tests/ImmutableArrayTest.cs
@@ -1985,6 +1985,7 @@ public void IStructuralEquatableEqualsNullComparerInvalid()
         [Theory]
         [MemberData(nameof(IStructuralEquatableGetHashCodeData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50579", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36876", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IStructuralEquatableGetHashCode(IEnumerable<int> source, IEqualityComparer comparer)
         {
             var array = source.ToImmutableArray();
diff --git a/src/libraries/System.Console/tests/CancelKeyPress.cs b/src/libraries/System.Console/tests/CancelKeyPress.cs
index db1e4e67ab2206..4ce7a8f3fef39b 100644
--- a/src/libraries/System.Console/tests/CancelKeyPress.cs
+++ b/src/libraries/System.Console/tests/CancelKeyPress.cs
@@ -13,7 +13,7 @@ public partial class CancelKeyPressTests
     private const int WaitFailTestTimeoutSeconds = 30;
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void CanAddAndRemoveHandler()
     {
         ConsoleCancelEventHandler handler = (sender, e) =>
diff --git a/src/libraries/System.Console/tests/Color.cs b/src/libraries/System.Console/tests/Color.cs
index 2cc8c585140928..1ee9e32748dabe 100644
--- a/src/libraries/System.Console/tests/Color.cs
+++ b/src/libraries/System.Console/tests/Color.cs
@@ -12,7 +12,7 @@
 public class Color
 {
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void InvalidColors()
     {
         AssertExtensions.Throws<ArgumentException>(null, () => Console.BackgroundColor = (ConsoleColor)42);
@@ -20,7 +20,7 @@ public static void InvalidColors()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void RoundtrippingColor()
     {
         Console.BackgroundColor = Console.BackgroundColor;
@@ -49,7 +49,7 @@ public static void BackgroundColor_Throws_PlatformNotSupportedException()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void RedirectedOutputDoesNotUseAnsiSequences()
     {
         // Make sure that redirecting to a memory stream causes Console not to write out the ANSI sequences
diff --git a/src/libraries/System.Console/tests/ConsoleEncoding.cs b/src/libraries/System.Console/tests/ConsoleEncoding.cs
index d52d93c9282201..ce3bfc698501c1 100644
--- a/src/libraries/System.Console/tests/ConsoleEncoding.cs
+++ b/src/libraries/System.Console/tests/ConsoleEncoding.cs
@@ -22,7 +22,7 @@ public static IEnumerable<object[]> InputData()
 
     [Theory]
     [MemberData(nameof(InputData))]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void TestEncoding(string inputString)
     {
         TextWriter outConsoleStream = Console.Out;
@@ -79,7 +79,7 @@ public void TestEncoding(string inputString)
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void TestValidEncodings()
     {
         Action<Encoding> check = encoding =>
diff --git a/src/libraries/System.Console/tests/ReadAndWrite.cs b/src/libraries/System.Console/tests/ReadAndWrite.cs
index c4a13b21b644e0..29bb58dfae0b07 100644
--- a/src/libraries/System.Console/tests/ReadAndWrite.cs
+++ b/src/libraries/System.Console/tests/ReadAndWrite.cs
@@ -258,7 +258,7 @@ private static unsafe void ValidateConsoleEncoding(Encoding encoding)
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static unsafe void OutputEncodingPreamble()
     {
         Encoding curEncoding = Console.OutputEncoding;
@@ -281,7 +281,7 @@ public static unsafe void OutputEncodingPreamble()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static unsafe void OutputEncoding()
     {
         Encoding curEncoding = Console.OutputEncoding;
@@ -349,7 +349,7 @@ public static void InputEncoding_Getter_Throws_PlatformNotSupportedException()
     };
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void ReadAndReadLine()
     {
         TextWriter savedStandardOutput = Console.Out;
diff --git a/src/libraries/System.Console/tests/SetIn.cs b/src/libraries/System.Console/tests/SetIn.cs
index 46780d62e428e6..111fa7bcc6aa40 100644
--- a/src/libraries/System.Console/tests/SetIn.cs
+++ b/src/libraries/System.Console/tests/SetIn.cs
@@ -11,7 +11,7 @@
 public class SetIn
 {
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void SetInThrowsOnNull()
     {
         TextReader savedIn = Console.In;
@@ -26,7 +26,7 @@ public static void SetInThrowsOnNull()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void SetInReadLine()
     {
         const string TextStringFormat = "Test {0}";
diff --git a/src/libraries/System.Console/tests/SyncTextReader.cs b/src/libraries/System.Console/tests/SyncTextReader.cs
index 3a5c0b5617b17f..dd64326275a676 100644
--- a/src/libraries/System.Console/tests/SyncTextReader.cs
+++ b/src/libraries/System.Console/tests/SyncTextReader.cs
@@ -6,7 +6,7 @@
 using System.Text;
 using Xunit;
 
-
+[SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
 public class SyncTextReader
 {
     // NOTE: These tests test the underlying SyncTextReader by
@@ -78,7 +78,6 @@ private static void Test(string content, Action action)
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadToEnd()
     {
         var expected = string.Join(Environment.NewLine, s_testLines);
@@ -93,7 +92,6 @@ public void ReadToEnd()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadBlock()
     {
         var expected = new[] { 'H', 'e', 'l', 'l', 'o' };
@@ -112,7 +110,6 @@ public void ReadBlock()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void Read()
     {
         var expected = new[] { 'H', 'e', 'l', 'l', 'o' };
@@ -131,7 +128,6 @@ public void Read()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void Peek()
     {
         const string expected = "ABC";
@@ -145,7 +141,6 @@ public void Peek()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadToEndAsync()
     {
         var expected = string.Join(Environment.NewLine, s_testLines);
@@ -160,7 +155,6 @@ public void ReadToEndAsync()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadBlockAsync()
     {
         var expected = new[] { 'H', 'e', 'l', 'l', 'o' };
@@ -185,7 +179,6 @@ public void ReadBlockAsync()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadAsync()
     {
         var expected = new[] { 'H', 'e', 'l', 'l', 'o' };
@@ -210,7 +203,6 @@ public void ReadAsync()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
     public void ReadLineAsync()
     {
         var expected = string.Join(Environment.NewLine, s_testLines);
diff --git a/src/libraries/System.Console/tests/TermInfo.cs b/src/libraries/System.Console/tests/TermInfo.cs
index bffe8ff382d7fb..85f1ee89c5e73b 100644
--- a/src/libraries/System.Console/tests/TermInfo.cs
+++ b/src/libraries/System.Console/tests/TermInfo.cs
@@ -27,6 +27,7 @@ public class TermInfo
 
     [Fact]
     [PlatformSpecific(TestPlatforms.AnyUnix)]  // Tests TermInfo
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/36878", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public void VerifyInstalledTermInfosParse()
     {
         bool foundAtLeastOne = false;
@@ -61,6 +62,7 @@ public void VerifyInstalledTermInfosParse()
 
     [Fact]
     [PlatformSpecific(TestPlatforms.AnyUnix)] // Tests TermInfo
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/36878", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public void VerifyTermInfoSupportsNewAndLegacyNcurses()
     {
         MethodInfo readDbMethod = typeof(Console).GetTypeInfo().Assembly.GetType(TerminfoDatabaseType).GetTypeInfo().GetDeclaredMethods(ReadDatabaseMethod).Where(m => m.GetParameters().Count() == 2).Single();
@@ -85,6 +87,7 @@ public void VerifyTermInfoSupportsNewAndLegacyNcurses()
     [InlineData("mach-color", "\u001B\u005B\u00330m", "\u001B\u005B\u00340m", 0)]
     [InlineData("mach-color", "\u001B\u005B\u00335m", "\u001B\u005B\u00345m", 5)]
     [InlineData("mach-color", "\u001B\u005B\u003312m", "\u001B\u005B\u003412m", 12)]
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/36878", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public void TermInfoVerification(string termToTest, string expectedForeground, string expectedBackground, int colorValue)
     {
         object db = ReadTermInfoDatabase(termToTest);
@@ -108,6 +111,7 @@ public void EmuTermInfoDoesntBreakParser()
 
     [Fact]
     [PlatformSpecific(TestPlatforms.AnyUnix)]  // Tests TermInfo
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/36878", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public void TryingToLoadTermThatDoesNotExistDoesNotThrow()
     {
         const string NonexistentTerm = "foobar____";
diff --git a/src/libraries/System.Console/tests/ThreadSafety.cs b/src/libraries/System.Console/tests/ThreadSafety.cs
index ddc074760701e8..778bb958c0a482 100644
--- a/src/libraries/System.Console/tests/ThreadSafety.cs
+++ b/src/libraries/System.Console/tests/ThreadSafety.cs
@@ -12,7 +12,7 @@ public class ThreadSafety
     const int NumberOfIterations = 100;
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void OpenStandardXXXCanBeCalledConcurrently()
     {
         Parallel.For(0, NumberOfIterations, i =>
@@ -41,7 +41,7 @@ public static void OpenStandardXXXCanBeCalledConcurrently()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void SetStandardXXXCanBeCalledConcurrently()
     {
         TextReader savedStandardInput = Console.In;
@@ -84,7 +84,7 @@ public static void SetStandardXXXCanBeCalledConcurrently()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void ReadMayBeCalledConcurrently()
     {
         const char TestChar = '+';
diff --git a/src/libraries/System.Console/tests/Timeout.cs b/src/libraries/System.Console/tests/Timeout.cs
index f8630073ed55ff..c0d128602bc05e 100644
--- a/src/libraries/System.Console/tests/Timeout.cs
+++ b/src/libraries/System.Console/tests/Timeout.cs
@@ -11,7 +11,7 @@
 public class TimeOut
 {
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void OpenStandardXXX_WriteTimeOut()
     {
         using (Stream standardOut = Console.OpenStandardOutput(), standardIn = Console.OpenStandardInput(), standardError = Console.OpenStandardError())
@@ -27,7 +27,7 @@ public static void OpenStandardXXX_WriteTimeOut()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void OpenStandardXXX_ReadTimeOut()
     {
         using (Stream standardOut = Console.OpenStandardOutput(), standardIn = Console.OpenStandardInput(), standardError = Console.OpenStandardError())
@@ -43,7 +43,7 @@ public static void OpenStandardXXX_ReadTimeOut()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void OpenStandardXXX_CanTimeOut()
     {
         using (Stream standardOut = Console.OpenStandardOutput(), standardIn = Console.OpenStandardInput(), standardError = Console.OpenStandardError())
diff --git a/src/libraries/System.Console/tests/WindowAndCursorProps.cs b/src/libraries/System.Console/tests/WindowAndCursorProps.cs
index 32df8909e11b64..0e1763e84b20bc 100644
--- a/src/libraries/System.Console/tests/WindowAndCursorProps.cs
+++ b/src/libraries/System.Console/tests/WindowAndCursorProps.cs
@@ -11,7 +11,7 @@
 public class WindowAndCursorProps
 {
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void BufferWidth_GetUnix_ReturnsWindowWidth()
     {
         Assert.Equal(Console.WindowWidth, Console.BufferWidth);
@@ -25,7 +25,7 @@ public static void BufferWidth_SetUnix_ThrowsPlatformNotSupportedException()
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void BufferHeight_GetUnix_ReturnsWindowHeight()
     {
         Assert.Equal(Console.WindowHeight, Console.BufferHeight);
@@ -62,7 +62,7 @@ public static void WindowWidth_SetInvalid_ThrowsArgumentOutOfRangeException(int
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void WindowWidth_GetUnix_Success()
     {
         // Validate that Console.WindowWidth returns some value in a non-redirected o/p.
@@ -94,7 +94,7 @@ public static void WindowHeight_SetInvalid_ThrowsArgumentOutOfRangeException(int
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void WindowHeight_GetUnix_Success()
     {
         // Validate that Console.WindowHeight returns some value in a non-redirected o/p.
@@ -110,7 +110,7 @@ public static void WindowHeight_SetUnix_ThrowsPlatformNotSupportedException()
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void LargestWindowWidth_UnixGet_ReturnsExpected()
     {
         Helpers.RunInNonRedirectedOutput((data) => Assert.Equal(Console.WindowWidth, Console.LargestWindowWidth));
@@ -118,7 +118,7 @@ public static void LargestWindowWidth_UnixGet_ReturnsExpected()
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     public static void LargestWindowHeight_UnixGet_ReturnsExpected()
     {
         Helpers.RunInNonRedirectedOutput((data) => Assert.Equal(Console.WindowHeight, Console.LargestWindowHeight));
@@ -191,7 +191,7 @@ public static void CursorVisible_GetUnix_ThrowsPlatformNotSupportedException()
     }
 
     [Theory]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]  // Expected behavior specific to Unix
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]  // Expected behavior specific to Unix
     [InlineData(true)]
     [InlineData(false)]
     public static void CursorVisible_SetUnixRedirected_Nop(bool value)
@@ -337,7 +337,7 @@ public static void SetCursorPosition_Throws_PlatformNotSupportedException()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void SetCursorPosition_Invoke_Success()
     {
         if (!OperatingSystem.IsWindows() || (!Console.IsInputRedirected && !Console.IsOutputRedirected))
@@ -364,7 +364,7 @@ public void SetCursorPosition_InvalidPosition_ThrowsArgumentOutOfRangeException(
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public static void GetCursorPosition_Invoke_ReturnsExpected()
     {
         if (!Console.IsInputRedirected && !Console.IsOutputRedirected)
@@ -391,7 +391,7 @@ public static void GetCursorPosition_Invoke_ReturnsExpected()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void CursorLeft_Set_GetReturnsExpected()
     {
         if (!Console.IsInputRedirected && !Console.IsOutputRedirected)
@@ -413,7 +413,7 @@ public void CursorLeft_Set_GetReturnsExpected()
     [Theory]
     [InlineData(-1)]
     [InlineData(short.MaxValue + 1)]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void CursorLeft_SetInvalid_ThrowsArgumentOutOfRangeException(int value)
     {
         if (PlatformDetection.IsWindows && Console.IsOutputRedirected)
@@ -434,7 +434,7 @@ public void CursorLeft_Setter_Throws_PlatformNotSupportedException()
     }
 
     [Fact]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void CursorTop_Set_GetReturnsExpected()
     {
         if (!Console.IsInputRedirected && !Console.IsOutputRedirected)
@@ -456,7 +456,7 @@ public void CursorTop_Set_GetReturnsExpected()
     [Theory]
     [InlineData(-1)]
     [InlineData(short.MaxValue + 1)]
-    [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+    [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
     public void CursorTop_SetInvalid_ThrowsArgumentOutOfRangeException(int value)
     {
         if (PlatformDetection.IsWindows & Console.IsOutputRedirected)
@@ -505,7 +505,7 @@ public void CursorSize_SetInvalidValue_ThrowsArgumentOutOfRangeException(int val
     }
 
     [Fact]
-    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser)]
+    [PlatformSpecific(TestPlatforms.AnyUnix & ~TestPlatforms.Browser & ~TestPlatforms.iOS & ~TestPlatforms.tvOS)]
     public void CursorSize_GetUnix_ReturnsExpected()
     {
         Assert.Equal(100, Console.CursorSize);
diff --git a/src/libraries/System.Data.Common/tests/System/Data/Common/DbProviderFactoriesTests.cs b/src/libraries/System.Data.Common/tests/System/Data/Common/DbProviderFactoriesTests.cs
index b758b3967c62ee..321c014e0bed9d 100644
--- a/src/libraries/System.Data.Common/tests/System/Data/Common/DbProviderFactoriesTests.cs
+++ b/src/libraries/System.Data.Common/tests/System/Data/Common/DbProviderFactoriesTests.cs
@@ -38,6 +38,7 @@ public void GetFactoryNoRegistrationTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetFactoryWithInvariantNameTest()
         {
             ClearRegisteredFactories();
@@ -49,6 +50,7 @@ public void GetFactoryWithInvariantNameTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetFactoryWithDbConnectionTest()
         {
             ClearRegisteredFactories();
@@ -60,6 +62,7 @@ public void GetFactoryWithDbConnectionTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetFactoryWithDataRowTest()
         {
             ClearRegisteredFactories();
@@ -67,6 +70,7 @@ public void GetFactoryWithDataRowTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RegisterFactoryWithTypeNameTest()
         {
             ClearRegisteredFactories();
@@ -74,6 +78,7 @@ public void RegisterFactoryWithTypeNameTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RegisterFactoryWithTypeTest()
         {
             ClearRegisteredFactories();
@@ -81,6 +86,7 @@ public void RegisterFactoryWithTypeTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RegisterFactoryWithInstanceTest()
         {
             ClearRegisteredFactories();
@@ -96,6 +102,7 @@ public void RegisterFactoryWithWrongTypeTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RegisterFactoryWithBadInvariantNameTest()
         {
             ClearRegisteredFactories();
@@ -104,6 +111,7 @@ public void RegisterFactoryWithBadInvariantNameTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RegisterFactoryWithAssemblyQualifiedNameTest()
         {
             ClearRegisteredFactories();
@@ -127,6 +135,7 @@ public void RegisterFactoryWithWrongAssemblyQualifiedNameTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void UnregisterFactoryTest()
         {
             ClearRegisteredFactories();
@@ -137,6 +146,7 @@ public void UnregisterFactoryTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TryGetFactoryTest()
         {
             ClearRegisteredFactories();
@@ -149,6 +159,7 @@ public void TryGetFactoryTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ReplaceFactoryWithRegisterFactoryWithTypeTest()
         {
             ClearRegisteredFactories();
@@ -163,6 +174,7 @@ public void ReplaceFactoryWithRegisterFactoryWithTypeTest()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36879", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetProviderInvariantNamesTest()
         {
             ClearRegisteredFactories();
diff --git a/src/libraries/System.Diagnostics.Debug/tests/DebugTestsNoListeners.cs b/src/libraries/System.Diagnostics.Debug/tests/DebugTestsNoListeners.cs
index edc3265e22bb05..cabe5a7f4ec9ed 100644
--- a/src/libraries/System.Diagnostics.Debug/tests/DebugTestsNoListeners.cs
+++ b/src/libraries/System.Diagnostics.Debug/tests/DebugTestsNoListeners.cs
@@ -68,6 +68,7 @@ public void Debug_WriteNull_SkipsIndentation()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50570", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36882", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Debug_WriteLineNull_IndentsEmptyStringProperly()
         {
             Debug.Indent();
@@ -210,6 +211,7 @@ public void IndentSize_Set_GetReturnsExpected(int indentSize, int expectedIndent
         [InlineData(0, 0)]
         [InlineData(1, 1)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50570", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36882", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IndentLevel_Set_GetReturnsExpected(int indentLevel, int expectedIndentLevel)
         {
             Debug.IndentLevel = indentLevel;
diff --git a/src/libraries/System.Diagnostics.Debug/tests/DebugTestsUsingListeners.cs b/src/libraries/System.Diagnostics.Debug/tests/DebugTestsUsingListeners.cs
index a7a7f5eb3185a9..52b428efce742b 100644
--- a/src/libraries/System.Diagnostics.Debug/tests/DebugTestsUsingListeners.cs
+++ b/src/libraries/System.Diagnostics.Debug/tests/DebugTestsUsingListeners.cs
@@ -197,6 +197,7 @@ public void Trace_Refresh_ResetsIndentSize()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50570", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36882", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Trace_ClearTraceListeners_StopsWritingToDebugger()
         {
             VerifyLogged(() => Debug.Write("pizza"), "pizza");
@@ -231,6 +232,7 @@ public void TraceWriteIf()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50570", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36882", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TraceWriteLineIf()
         {
             VerifyLogged(() => Trace.WriteLineIf(true, 5), "5" + Environment.NewLine);
diff --git a/src/libraries/System.Diagnostics.DiagnosticSource/tests/TestWithConfigSwitches/ActivityTests.cs b/src/libraries/System.Diagnostics.DiagnosticSource/tests/TestWithConfigSwitches/ActivityTests.cs
index 06cb5e3581f9ef..5890e43abd37b0 100644
--- a/src/libraries/System.Diagnostics.DiagnosticSource/tests/TestWithConfigSwitches/ActivityTests.cs
+++ b/src/libraries/System.Diagnostics.DiagnosticSource/tests/TestWithConfigSwitches/ActivityTests.cs
@@ -7,6 +7,7 @@
 namespace System.Diagnostics.Tests
 {
     [ActiveIssue("https://github.com/dotnet/runtime/issues/37073", TestPlatforms.Android)]
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51376", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
     public class ActivityTests : IDisposable
     {
         [Fact]
diff --git a/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs b/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
index d288f236496264..1ffe9f0f24ca47 100644
--- a/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
+++ b/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
@@ -31,6 +31,7 @@ private static bool IsAdmin_IsNotNano_RemoteExecutorIsSupported
             => PlatformDetection.IsWindowsAndElevated && PlatformDetection.IsNotWindowsNanoServer && RemoteExecutor.IsSupported;
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51386", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TestEnvironmentProperty()
         {
             Assert.NotEqual(0, new Process().StartInfo.Environment.Count);
@@ -41,7 +42,6 @@ public void TestEnvironmentProperty()
             // with current environmental variables.
 
             IDictionary<string, string> environment = psi.Environment;
-
             Assert.NotEqual(0, environment.Count);
 
             int countItems = environment.Count;
@@ -773,6 +773,7 @@ public void Verbs_GetUnix_ReturnsEmpty()
 
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // Test case is specific to Unix
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51386", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TestEnvironmentVariablesPropertyUnix()
         {
             ProcessStartInfo psi = new ProcessStartInfo();
diff --git a/src/libraries/System.Diagnostics.Process/tests/ProcessTests.Unix.cs b/src/libraries/System.Diagnostics.Process/tests/ProcessTests.Unix.cs
index dccedb7e01dc5d..2ce95e3408a9c2 100644
--- a/src/libraries/System.Diagnostics.Process/tests/ProcessTests.Unix.cs
+++ b/src/libraries/System.Diagnostics.Process/tests/ProcessTests.Unix.cs
@@ -158,6 +158,7 @@ public void ProcessStart_UseShellExecute_OnUnix_SuccessWhenProgramInstalled(bool
 
         [Fact]
         [SkipOnPlatform(TestPlatforms.OSX, "On OSX, ProcessName returns the script interpreter.")]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessNameMatchesScriptName()
         {
             string scriptName = GetTestFileName();
@@ -476,6 +477,7 @@ public void TestBasePriorityOnUnix()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void TestStartOnUnixWithBadPermissions()
         {
             string path = GetTestFilePath();
@@ -487,6 +489,7 @@ public void TestStartOnUnixWithBadPermissions()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void TestStartOnUnixWithBadFormat()
         {
             string path = GetTestFilePath();
diff --git a/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs b/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs
index 8ece605da6f1cc..7858d428649f18 100644
--- a/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs
+++ b/src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs
@@ -172,18 +172,21 @@ public void TestExited_SynchronizingObject(bool invokeRequired)
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessStart_TryExitCommandAsFileName_ThrowsWin32Exception()
         {
             Assert.Throws<Win32Exception>(() => Process.Start(new ProcessStartInfo { UseShellExecute = false, FileName = "exit", Arguments = "42" }));
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessStart_UseShellExecuteFalse_FilenameIsUrl_ThrowsWin32Exception()
         {
             Assert.Throws<Win32Exception>(() => Process.Start(new ProcessStartInfo { UseShellExecute = false, FileName = "https://www.github.com/corefx" }));
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessStart_TryOpenFolder_UseShellExecuteIsFalse_ThrowsWin32Exception()
         {
             Assert.Throws<Win32Exception>(() => Process.Start(new ProcessStartInfo { UseShellExecute = false, FileName = Path.GetTempPath() }));
@@ -273,6 +276,7 @@ public void ProcessStart_UseShellExecute_OnWindows_DoesNotThrow(bool isFolder)
             nameof(PlatformDetection.IsNotWindowsNanoServer), nameof(PlatformDetection.IsNotWindowsIoTCore))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34685", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [InlineData(true), InlineData(false)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessStart_UseShellExecute_Executes(bool filenameAsUrl)
         {
             string filename = WriteScriptFile(TestDirectory, GetTestFileName(), returnValue: 42);
@@ -341,6 +345,7 @@ public void ProcessStart_UseShellExecute_ExecuteOrder()
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsServerCore),
             nameof(PlatformDetection.IsNotWindowsNanoServer), nameof(PlatformDetection.IsNotWindowsIoTCore))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34685", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void ProcessStart_UseShellExecute_WorkingDirectory()
         {
             // Create a directory that will ProcessStartInfo.WorkingDirectory
@@ -470,6 +475,7 @@ public void HasExited_GetNotStarted_ThrowsInvalidOperationException()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void Kill_NotStarted_ThrowsInvalidOperationException()
         {
             var process = new Process();
@@ -542,7 +548,7 @@ public void TestMaxWorkingSet()
         }
 
         [Fact]
-        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "Getting MaxWorkingSet is not supported on OSX and BSD.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD | TestPlatforms.iOS | TestPlatforms.tvOS, "Getting MaxWorkingSet is not supported on OSX, BSD, iOS, and tvOS.")]
         public void MaxWorkingSet_GetNotStarted_ThrowsInvalidOperationException()
         {
             var process = new Process();
@@ -597,7 +603,7 @@ public void TestMinWorkingSet()
         }
 
         [Fact]
-        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "Getting MinWorkingSet is not supported on OSX and BSD.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD | TestPlatforms.iOS | TestPlatforms.tvOS, "Getting MinWorkingSet is not supported on OSX, BSD, iOS, and tvOS.")]
         public void MinWorkingSet_GetNotStarted_ThrowsInvalidOperationException()
         {
             var process = new Process();
@@ -1375,6 +1381,7 @@ public void CanBeFinalized()
         [Theory]
         [InlineData(false)]
         [InlineData(true)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS, or tvOS.")]
         public void TestStartWithMissingFile(bool fullPath)
         {
             string path = Guid.NewGuid().ToString("N");
diff --git a/src/libraries/System.Diagnostics.StackTrace/tests/StackTraceSymbolsTests.cs b/src/libraries/System.Diagnostics.StackTrace/tests/StackTraceSymbolsTests.cs
index 47eb6f07b700fe..a095dc87007c08 100644
--- a/src/libraries/System.Diagnostics.StackTrace/tests/StackTraceSymbolsTests.cs
+++ b/src/libraries/System.Diagnostics.StackTrace/tests/StackTraceSymbolsTests.cs
@@ -10,6 +10,7 @@ namespace System.Diagnostics.SymbolStore.Tests
     public class StackTraceSymbolsTests
     {
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51399", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void StackTraceSymbolsDoNotLockFile()
         {
             var asmPath = AssemblyPathHelper.GetAssemblyLocation(typeof(StackTraceSymbolsTests).Assembly);
diff --git a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsManifestNegative.cs b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsManifestNegative.cs
index 04b433395af4e0..2ee59adf59464f 100644
--- a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsManifestNegative.cs
+++ b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsManifestNegative.cs
@@ -59,6 +59,7 @@ private static string GetResourceStringFromReflection(string key)
         /// </summary>
         [Fact]
         [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework, "https://github.com/dotnet/runtime/issues/21421")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_GenerateManifest_InvalidEventSources()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
diff --git a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsTraits.cs b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsTraits.cs
index 2b1a208ae8c0b6..03369ed4ff12fc 100644
--- a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsTraits.cs
+++ b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsTraits.cs
@@ -29,6 +29,7 @@ public class TestsTraits
         /// Tests EventSource Traits.
         /// </summary>
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_EventSource_Traits_Contract()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -45,6 +46,7 @@ public void Test_EventSource_Traits_Contract()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_EventSource_Traits_Dynamic()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
diff --git a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsUserErrors.cs b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsUserErrors.cs
index 7748cd54ac08b0..58347d9dcfcda2 100644
--- a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsUserErrors.cs
+++ b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsUserErrors.cs
@@ -64,6 +64,7 @@ private void Test_BadTypes_Manifest(EventSource source)
         /// Test the
         /// </summary>
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsNanoServer))] // ActiveIssue: https://github.com/dotnet/runtime/issues/26197
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_BadEventSource_MismatchedIds()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
diff --git a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWrite.cs b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWrite.cs
index c8abf5f8844e46..a2c4dffb8c846e 100644
--- a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWrite.cs
+++ b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWrite.cs
@@ -37,6 +37,7 @@ private struct PartB_UserInfo
         /// </summary>
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/21564", TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_Write_T_EventListener()
         {
             using (var listener = new EventListenerListener())
@@ -51,6 +52,7 @@ public void Test_Write_T_EventListener()
         /// </summary>
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/21564", TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_Write_T_EventListener_UseEvents()
         {
             Test_Write_T(new EventListenerListener(true));
diff --git a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWriteEventToListener.cs b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWriteEventToListener.cs
index 1488e00955a3b3..0c08ee23202d75 100644
--- a/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWriteEventToListener.cs
+++ b/src/libraries/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestsWriteEventToListener.cs
@@ -18,6 +18,7 @@ public partial class TestsWriteEventToListener
     {
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/21569", TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_WriteEvent_ArgsBasicTypes()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -172,6 +173,7 @@ public void Test_WriteEvent_ArgsBasicTypes()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/21569", TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_WriteEvent_ArgsCornerCases()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -205,6 +207,7 @@ public void Test_WriteEvent_ArgsCornerCases()
         static partial void Test_WriteEvent_ArgsCornerCases_TestEtw(EventSourceTest log);
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_WriteEvent_InvalidCalls()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -227,6 +230,7 @@ public void Test_WriteEvent_InvalidCalls()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_WriteEvent_ToChannel_Coverage()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -241,6 +245,7 @@ public void Test_WriteEvent_ToChannel_Coverage()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/21569", TargetFrameworkMonikers.NetFramework)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_WriteEvent_ZeroKwds()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -277,6 +282,7 @@ public void Test_WriteEvent_ZeroKwds()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_EventSourceCreatedEvents_BeforeListener()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
@@ -340,6 +346,7 @@ public void Test_EventSourceCreatedEvents_BeforeListener()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51382", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Test_EventSourceCreatedEvents_AfterListener()
         {
             TestUtilities.CheckNoEventSourcesRunning("Start");
diff --git a/src/libraries/System.IO.Compression.Brotli/tests/BrotliGoogleTestData.cs b/src/libraries/System.IO.Compression.Brotli/tests/BrotliGoogleTestData.cs
index dc86a757fc65a1..78f69aa5128713 100644
--- a/src/libraries/System.IO.Compression.Brotli/tests/BrotliGoogleTestData.cs
+++ b/src/libraries/System.IO.Compression.Brotli/tests/BrotliGoogleTestData.cs
@@ -32,6 +32,7 @@ public static IEnumerable<object[]> GoogleTestData()
 
         [Theory]
         [MemberData(nameof(GoogleTestData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DecompressFile(string fileName)
         {
             byte[] bytes = File.ReadAllBytes(CompressedTestFile(fileName));
@@ -42,6 +43,7 @@ public void DecompressFile(string fileName)
 
         [Theory]
         [MemberData(nameof(GoogleTestData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RoundtripCompressDecompressFile(string fileName)
         {
             byte[] bytes = File.ReadAllBytes(fileName);
diff --git a/src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs b/src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs
index 3960233e5eafa8..316e3ba7a08454 100644
--- a/src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs
+++ b/src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs
@@ -58,6 +58,7 @@ public void GetMaxCompressedSize_Basic()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetMaxCompressedSize()
         {
             string uncompressedFile = UncompressedTestFile();
@@ -71,6 +72,7 @@ public void GetMaxCompressedSize()
         /// Test to ensure that when given an empty Destination span, the decoder will consume no input and write no output.
         /// </summary>
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Decompress_WithEmptyDestination()
         {
             string testFile = UncompressedTestFile();
@@ -114,6 +116,7 @@ public void Decompress_WithEmptySource()
         /// Test to ensure that when given an empty Destination span, the encoder consume no input and write no output
         /// </summary>
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36884", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Compress_WithEmptyDestination()
         {
             string testFile = UncompressedTestFile();
diff --git a/src/libraries/System.IO.Compression.ZipFile/tests/ZipFile.Extract.cs b/src/libraries/System.IO.Compression.ZipFile/tests/ZipFile.Extract.cs
index 9bbfd271d2e474..b71e03f7558b21 100644
--- a/src/libraries/System.IO.Compression.ZipFile/tests/ZipFile.Extract.cs
+++ b/src/libraries/System.IO.Compression.ZipFile/tests/ZipFile.Extract.cs
@@ -34,6 +34,7 @@ public void ExtractToDirectoryNull()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52616", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ExtractToDirectoryUnicode()
         {
             string zipFileName = zfile("unicode.zip");
diff --git a/src/libraries/System.IO.Compression.ZipFile/tests/ZipFileExtensions.ZipArchive.Extract.cs b/src/libraries/System.IO.Compression.ZipFile/tests/ZipFileExtensions.ZipArchive.Extract.cs
index e0dfc37788d936..d7b97eb9681d20 100644
--- a/src/libraries/System.IO.Compression.ZipFile/tests/ZipFileExtensions.ZipArchive.Extract.cs
+++ b/src/libraries/System.IO.Compression.ZipFile/tests/ZipFileExtensions.ZipArchive.Extract.cs
@@ -22,6 +22,7 @@ public void ExtractToDirectoryExtension()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52616", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ExtractToDirectoryExtension_Unicode()
         {
             using (ZipArchive archive = ZipFile.OpenRead(zfile("unicode.zip")))
diff --git a/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.Directory.Move.cs b/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.Directory.Move.cs
index b40fac4e7602f5..63e854dd0c008c 100644
--- a/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.Directory.Move.cs
+++ b/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.Directory.Move.cs
@@ -43,6 +43,7 @@ public void Directory_Move_Multiple_From_Watched_To_Unwatched_Mac(int filesCount
         [InlineData(1)]
         [InlineData(2)]
         [InlineData(3)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51393", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Directory_Move_Multiple_From_Watched_To_Unwatched(int filesCount)
         {
             DirectoryMove_Multiple_FromWatchedToUnwatched(filesCount, skipOldEvents: false);
diff --git a/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs b/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs
index 05ba2620929768..c9a36a577962f8 100644
--- a/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs
+++ b/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs
@@ -47,6 +47,7 @@ public void File_Move_Multiple_From_Watched_To_Unwatched_Mac(int filesCount)
         [InlineData(1)]
         [InlineData(2)]
         [InlineData(3)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51393", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void File_Move_Multiple_From_Watched_To_Unwatched(int filesCount)
         {
             FileMove_Multiple_FromWatchedToUnwatched(filesCount, skipOldEvents: false);
diff --git a/src/libraries/System.IO.FileSystem/tests/Base/FileGetSetAttributes.cs b/src/libraries/System.IO.FileSystem/tests/Base/FileGetSetAttributes.cs
index 6e2d5a4a7753c1..2c01cd430d32f3 100644
--- a/src/libraries/System.IO.FileSystem/tests/Base/FileGetSetAttributes.cs
+++ b/src/libraries/System.IO.FileSystem/tests/Base/FileGetSetAttributes.cs
@@ -65,6 +65,7 @@ public void SettingInvalidAttributes_Unix(FileAttributes attributes)
         [Theory]
         [InlineData(FileAttributes.Hidden)]
         [PlatformSpecific(TestPlatforms.AnyUnix & ~(TestPlatforms.OSX | TestPlatforms.FreeBSD))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SettingInvalidAttributes_UnixExceptOSXAndFreeBSD(FileAttributes attributes)
         {
             string path = CreateItem();
diff --git a/src/libraries/System.IO.FileSystem/tests/Directory/CreateDirectory.cs b/src/libraries/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
index 7a69bf3aa28010..fb3a74305bca2c 100644
--- a/src/libraries/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
+++ b/src/libraries/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
@@ -201,6 +201,7 @@ public void AllowedSymbols()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DirectoryEqualToMaxDirectory_CanBeCreatedAllAtOnce()
         {
             DirectoryInfo testDir = Create(GetTestFilePath());
diff --git a/src/libraries/System.IO.FileSystem/tests/Directory/Exists.cs b/src/libraries/System.IO.FileSystem/tests/Directory/Exists.cs
index 067834f9094c45..107472c795059b 100644
--- a/src/libraries/System.IO.FileSystem/tests/Directory/Exists.cs
+++ b/src/libraries/System.IO.FileSystem/tests/Directory/Exists.cs
@@ -301,6 +301,7 @@ public void PathWithReservedDeviceNameAsPath_ReturnsFalse(string component)
 
         [Theory,
             MemberData(nameof(UncPathsWithoutShareName))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void UncPathWithoutShareNameAsPath_ReturnsFalse(string component)
         {
             Assert.False(Exists(component));
diff --git a/src/libraries/System.IO.FileSystem/tests/Directory/GetFileSystemEntries_str_str.cs b/src/libraries/System.IO.FileSystem/tests/Directory/GetFileSystemEntries_str_str.cs
index 45a056691c3d63..c4858914a43812 100644
--- a/src/libraries/System.IO.FileSystem/tests/Directory/GetFileSystemEntries_str_str.cs
+++ b/src/libraries/System.IO.FileSystem/tests/Directory/GetFileSystemEntries_str_str.cs
@@ -699,6 +699,7 @@ public void WindowsSearchPatternWhitespace()
 
         [Fact]
         [PlatformSpecific(CaseSensitivePlatforms)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SearchPatternCaseSensitive()
         {
             DirectoryInfo testDir = Directory.CreateDirectory(GetTestFilePath());
diff --git a/src/libraries/System.IO.FileSystem/tests/Directory/GetFiles.cs b/src/libraries/System.IO.FileSystem/tests/Directory/GetFiles.cs
index 33bb96aefb1b78..bec3ff78cf546f 100644
--- a/src/libraries/System.IO.FileSystem/tests/Directory/GetFiles.cs
+++ b/src/libraries/System.IO.FileSystem/tests/Directory/GetFiles.cs
@@ -42,6 +42,7 @@ public void EnumerateWithSymLinkToFile()
         }
 
         [ConditionalFact(nameof(AreAllLongPathsAvailable))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void EnumerateFilesOverLegacyMaxPath()
         {
             // We want to test that directories under the legacy MAX_PATH (260 characters, including the null) can iterate files
diff --git a/src/libraries/System.IO.FileSystem/tests/File/Create.cs b/src/libraries/System.IO.FileSystem/tests/File/Create.cs
index d89fcd26a5b9c2..a4a8de349f3bb3 100644
--- a/src/libraries/System.IO.FileSystem/tests/File/Create.cs
+++ b/src/libraries/System.IO.FileSystem/tests/File/Create.cs
@@ -188,6 +188,7 @@ public void LongFileName()
 
         [Fact]
         [PlatformSpecific(CaseSensitivePlatforms)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void CaseSensitive()
         {
             DirectoryInfo testDir = Directory.CreateDirectory(GetTestFilePath());
diff --git a/src/libraries/System.IO.FileSystem/tests/File/Exists.cs b/src/libraries/System.IO.FileSystem/tests/File/Exists.cs
index 4f0ca2af03a6fb..b37c8d94c32f3b 100644
--- a/src/libraries/System.IO.FileSystem/tests/File/Exists.cs
+++ b/src/libraries/System.IO.FileSystem/tests/File/Exists.cs
@@ -112,6 +112,7 @@ public void PathAlreadyExistsAsDirectory()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DirectoryLongerThanMaxDirectoryAsPath_DoesntThrow()
         {
             Assert.All((IOInputs.GetPathsLongerThanMaxDirectory(GetTestFilePath())), (path) =>
@@ -232,6 +233,7 @@ public void PathWithReservedDeviceNameAsPath_ReturnsFalse(string component)
 
         [Theory,
             MemberData(nameof(UncPathsWithoutShareName))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51371", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void UncPathWithoutShareNameAsPath_ReturnsFalse(string component)
         {
             Assert.False(Exists(component));
diff --git a/src/libraries/System.IO.FileSystem/tests/FileStream/LockUnlock.cs b/src/libraries/System.IO.FileSystem/tests/FileStream/LockUnlock.cs
index d2f7bf7ec62c15..bdd41d2c4e6288 100644
--- a/src/libraries/System.IO.FileSystem/tests/FileStream/LockUnlock.cs
+++ b/src/libraries/System.IO.FileSystem/tests/FileStream/LockUnlock.cs
@@ -58,7 +58,7 @@ public void LockUnlock_Unsupported_OSX()
         [InlineData(200, 50, 150)]
         [InlineData(200, 100, 100)]
         [InlineData(20, 2000, 1000)]
-        [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on macOS/iOS/tvOS/MacCatalyst.")]
         public void Lock_Unlock_Successful(long fileLength, long position, long length)
         {
             string path = GetTestFilePath();
@@ -75,7 +75,7 @@ public void Lock_Unlock_Successful(long fileLength, long position, long length)
         [InlineData(FileAccess.Read)]
         [InlineData(FileAccess.Write)]
         [InlineData(FileAccess.ReadWrite)]
-        [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on macOS/iOS/tvOS/MacCatalyst.")]
         public void Lock_Unlock_Successful_AlternateFileAccess(FileAccess fileAccess)
         {
             string path = GetTestFilePath();
@@ -89,7 +89,7 @@ public void Lock_Unlock_Successful_AlternateFileAccess(FileAccess fileAccess)
 
         [Theory]
         [InlineData(10, 0, 2, 3, 5)]
-        [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on macOS/iOS/tvOS/MacCatalyst.")]
         public void NonOverlappingRegions_Success(long fileLength, long firstPosition, long firstLength, long secondPosition, long secondLength)
         {
             string path = GetTestFilePath();
@@ -176,7 +176,7 @@ public void OverlappingRegionsFromSameProcess_AllowedOnUnix(long fileLength, lon
         [InlineData(10, 3, 5, 2, 6)]
         [InlineData(10, 3, 5, 2, 4)]
         [InlineData(10, 3, 5, 4, 6)]
-        [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on macOS/iOS/tvOS/MacCatalyst.")]
         public void OverlappingRegionsFromOtherProcess_ThrowsException(long fileLength, long firstPosition, long firstLength, long secondPosition, long secondLength)
         {
             string path = GetTestFilePath();
@@ -231,7 +231,7 @@ public void OverlappingRegionsFromOtherProcess_With_ReadLock_AllowedOnLinux()
         [InlineData(FileAccess.Read)]
         [InlineData(FileAccess.Write)]
         [InlineData(FileAccess.ReadWrite)]
-        [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on macOS/iOS/tvOS/MacCatalyst.")]
         public void OverlappingRegionsFromOtherProcess_With_WriteLock_ThrowsException(FileAccess fileAccess)
         {
             string path = GetTestFilePath();
diff --git a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateFromFile.Tests.cs b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateFromFile.Tests.cs
index 1df45e91bf5522..23654e823de680 100644
--- a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateFromFile.Tests.cs
+++ b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateFromFile.Tests.cs
@@ -293,6 +293,7 @@ public void InvalidArguments_Inheritability(HandleInheritability inheritability)
             new string[] { null, "CreateUniqueMapName()" },
             new long[] { 1, 256, -1 /*pagesize*/, 10000 },
             new MemoryMappedFileAccess[] { MemoryMappedFileAccess.ReadWrite })]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ValidArgumentCombinationsWithPath_ModesOpenOrCreate(
             FileMode mode, string mapName, long capacity, MemoryMappedFileAccess access)
         {
@@ -343,6 +344,7 @@ public void ValidArgumentCombinationsWithPath_ModesOpenOrCreate(
             new string[] { null, "CreateUniqueMapName()" },
             new long[] { 1, 256, -1 /*pagesize*/, 10000 },
             new MemoryMappedFileAccess[] { MemoryMappedFileAccess.Read, MemoryMappedFileAccess.ReadWrite, MemoryMappedFileAccess.CopyOnWrite })]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ValidArgumentCombinationsWithPath_ModeCreateNew(
             FileMode mode, string mapName, long capacity, MemoryMappedFileAccess access)
         {
@@ -367,6 +369,7 @@ public void ValidArgumentCombinationsWithPath_ModeCreateNew(
         [MemberData(nameof(MemberData_ValidNameCapacityCombinationsWithPath),
             new string[] { null, "CreateUniqueMapName()" },
             new long[] { 1, 256, -1 /*pagesize*/, 10000 })]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ValidArgumentCombinationsWithPath_ModeCreate(string mapName, long capacity)
         {
             using (TempFile file = new TempFile(GetTestFilePath(), capacity))
@@ -453,6 +456,7 @@ public static IEnumerable<object[]> MemberData_ValidNameCapacityCombinationsWith
             new MemoryMappedFileAccess[] { MemoryMappedFileAccess.Read, MemoryMappedFileAccess.ReadWrite, MemoryMappedFileAccess.CopyOnWrite },
             new HandleInheritability[] { HandleInheritability.None, HandleInheritability.Inheritable },
             new bool[] { false, true })]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ValidArgumentCombinationsWithStream(
             string mapName, long capacity, MemoryMappedFileAccess access, HandleInheritability inheritability, bool leaveOpen)
         {
diff --git a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateNew.Tests.cs b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateNew.Tests.cs
index 0d771fc85dab5d..e7c5ee2f80c3a6 100644
--- a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateNew.Tests.cs
+++ b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedFile.CreateNew.Tests.cs
@@ -188,6 +188,7 @@ public void ReusingNames_Windows(string name)
             new MemoryMappedFileAccess[] { MemoryMappedFileAccess.Read, MemoryMappedFileAccess.ReadExecute, MemoryMappedFileAccess.ReadWrite, MemoryMappedFileAccess.ReadWriteExecute, MemoryMappedFileAccess.CopyOnWrite },
             new MemoryMappedFileOptions[] { MemoryMappedFileOptions.None, MemoryMappedFileOptions.DelayAllocatePages },
             new HandleInheritability[] { HandleInheritability.None, HandleInheritability.Inheritable })]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ValidArgumentCombinations(
             string mapName, long capacity, MemoryMappedFileAccess access, MemoryMappedFileOptions options, HandleInheritability inheritability)
         {
diff --git a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewAccessor.Tests.cs b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewAccessor.Tests.cs
index 3193942d2fafd8..512748b10f9252 100644
--- a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewAccessor.Tests.cs
+++ b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewAccessor.Tests.cs
@@ -18,6 +18,7 @@ public class MemoryMappedViewAccessorTests : MemoryMappedFilesTestBase
         /// Test to validate the offset, size, and access parameters to MemoryMappedFile.CreateViewAccessor.
         /// </summary>
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void InvalidArguments()
         {
             int mapLength = s_pageSize.Value;
diff --git a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewStream.Tests.cs b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewStream.Tests.cs
index b1b4b1a610ee5a..5874800d73f44a 100644
--- a/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewStream.Tests.cs
+++ b/src/libraries/System.IO.MemoryMappedFiles/tests/MemoryMappedViewStream.Tests.cs
@@ -18,6 +18,7 @@ public class MemoryMappedViewStreamTests : MemoryMappedFilesTestBase
         /// Test to validate the offset, size, and access parameters to MemoryMappedFile.CreateViewAccessor.
         /// </summary>
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51375", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void InvalidArguments()
         {
             int mapLength = s_pageSize.Value;
diff --git a/src/libraries/System.IO.Ports/tests/System.IO.Ports.Tests.csproj b/src/libraries/System.IO.Ports/tests/System.IO.Ports.Tests.csproj
index 33c4af5c4ae0b8..1267d77477c099 100644
--- a/src/libraries/System.IO.Ports/tests/System.IO.Ports.Tests.csproj
+++ b/src/libraries/System.IO.Ports/tests/System.IO.Ports.Tests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-Linux;$(NetCoreAppCurrent)-OSX;$(NetCoreAppCurrent)-iOS;$(NetCoreAppCurrent)-FreeBSD;net461-windows</TargetFrameworks>
+    <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-Linux;$(NetCoreAppCurrent)-OSX;$(NetCoreAppCurrent)-FreeBSD;net461-windows</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="AssemblyInfo.cs" />
diff --git a/src/libraries/System.IO/tests/StreamReader/StreamReaderTests.cs b/src/libraries/System.IO/tests/StreamReader/StreamReaderTests.cs
index 4e4bb14d233e4a..4a2b91f8862b57 100644
--- a/src/libraries/System.IO/tests/StreamReader/StreamReaderTests.cs
+++ b/src/libraries/System.IO/tests/StreamReader/StreamReaderTests.cs
@@ -513,6 +513,7 @@ public async Task ReadBlockAsync_RepeatsReadsUntilReadDesiredAmount()
         [InlineData(1, false)]
         [InlineData(1, true)]
         [SkipOnPlatform(TestPlatforms.Browser, "Not supported on Browser.")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51390", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ReadAsync_Canceled_ThrowsException(int method, bool precanceled)
         {
             Func<StreamReader, CancellationToken, Task<int>> func = method switch
diff --git a/src/libraries/System.Linq.Expressions/tests/Array/ArrayArrayIndexTests.cs b/src/libraries/System.Linq.Expressions/tests/Array/ArrayArrayIndexTests.cs
index 1bd056bba9af38..9430253687acb5 100644
--- a/src/libraries/System.Linq.Expressions/tests/Array/ArrayArrayIndexTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Array/ArrayArrayIndexTests.cs
@@ -5,6 +5,7 @@
 
 namespace System.Linq.Expressions.Tests
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
     public static class ArrayArrayIndexTests
     {
         #region Boolean tests
diff --git a/src/libraries/System.Linq.Expressions/tests/Array/ArrayIndexTests.cs b/src/libraries/System.Linq.Expressions/tests/Array/ArrayIndexTests.cs
index 47079261232635..6eed3897f93d2a 100644
--- a/src/libraries/System.Linq.Expressions/tests/Array/ArrayIndexTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Array/ArrayIndexTests.cs
@@ -5,6 +5,7 @@
 
 namespace System.Linq.Expressions.Tests
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
     public static class ArrayIndexTests
     {
         #region Boolean tests
diff --git a/src/libraries/System.Linq.Expressions/tests/Array/NullableArrayIndexTests.cs b/src/libraries/System.Linq.Expressions/tests/Array/NullableArrayIndexTests.cs
index 91754a96bc27e8..e0932eef784ee2 100644
--- a/src/libraries/System.Linq.Expressions/tests/Array/NullableArrayIndexTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Array/NullableArrayIndexTests.cs
@@ -5,6 +5,7 @@
 
 namespace System.Linq.Expressions.Tests
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
     public static class NullableArrayIndexTests
     {
         #region NullableBool tests
diff --git a/src/libraries/System.Linq.Expressions/tests/BinaryOperators/Arithmetic/BinaryModuloTests.cs b/src/libraries/System.Linq.Expressions/tests/BinaryOperators/Arithmetic/BinaryModuloTests.cs
index c1a41f30861c20..4873b7769c3778 100644
--- a/src/libraries/System.Linq.Expressions/tests/BinaryOperators/Arithmetic/BinaryModuloTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/BinaryOperators/Arithmetic/BinaryModuloTests.cs
@@ -107,6 +107,7 @@ public static void CheckULongModuloTest(bool useInterpreter)
 
         [Theory]
         [ClassData(typeof(CompilationTypes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public static void CheckLongModuloTest(bool useInterpreter)
         {
             long[] array = new long[] { 0, 1, -1, long.MinValue, long.MaxValue };
diff --git a/src/libraries/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs b/src/libraries/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs
index 4891d348c29bbd..9848e3a86f9185 100644
--- a/src/libraries/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs
@@ -292,6 +292,7 @@ public void ResultPropertyFromParams(object value, int blockSize)
 
         [Theory]
         [MemberData(nameof(ConstantValuesAndSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public void ResultPropertyFromEnumerable(object value, int blockSize)
         {
             ConstantExpression constant = Expression.Constant(value, value.GetType());
diff --git a/src/libraries/System.Linq.Expressions/tests/Call/CallTests.cs b/src/libraries/System.Linq.Expressions/tests/Call/CallTests.cs
index 43e504c46dfe7f..f0c444283c87e8 100644
--- a/src/libraries/System.Linq.Expressions/tests/Call/CallTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Call/CallTests.cs
@@ -252,6 +252,7 @@ public static void CallByRefAttemptTailCall(bool useInterpreter)
 
         [Theory]
         [ClassData(typeof(CompilationTypes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51949", TestPlatforms.tvOS)]
         public static void Call_InstanceNullInside_ThrowsNullReferenceExceptionOnInvocation(bool useInterpreter)
         {
             Expression call = Expression.Call(Expression.Constant(null, typeof(NonGenericClass)), typeof(NonGenericClass).GetMethod(nameof(NonGenericClass.InstanceMethod)));
diff --git a/src/libraries/System.Linq.Expressions/tests/Cast/CastTests.cs b/src/libraries/System.Linq.Expressions/tests/Cast/CastTests.cs
index 090878f8fee7ec..bb83b061ec64c6 100644
--- a/src/libraries/System.Linq.Expressions/tests/Cast/CastTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Cast/CastTests.cs
@@ -7,6 +7,7 @@
 
 namespace System.Linq.Expressions.Tests
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
     public static class CastTests
     {
         #region Test methods
diff --git a/src/libraries/System.Linq.Expressions/tests/Member/MemberAccessTests.cs b/src/libraries/System.Linq.Expressions/tests/Member/MemberAccessTests.cs
index cca9a0e08c85b8..497416457ed07e 100644
--- a/src/libraries/System.Linq.Expressions/tests/Member/MemberAccessTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Member/MemberAccessTests.cs
@@ -8,6 +8,7 @@
 
 namespace System.Linq.Expressions.Tests
 {
+    [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
     public static class MemberAccessTests
     {
         private class UnreadableIndexableClass
diff --git a/src/libraries/System.Linq.Expressions/tests/SequenceTests/SequenceTests.cs b/src/libraries/System.Linq.Expressions/tests/SequenceTests/SequenceTests.cs
index 871721f81f4d23..44f50b5bdf894b 100644
--- a/src/libraries/System.Linq.Expressions/tests/SequenceTests/SequenceTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/SequenceTests/SequenceTests.cs
@@ -1486,6 +1486,7 @@ private static S TestConvertChecked<T, S>(T value, bool useInterpreter)
 
         [Theory]
         [ClassData(typeof(CompilationTypes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public static void ConvertNullToInt(bool useInterpreter)
         {
             Assert.Throws<NullReferenceException>(() =>
diff --git a/src/libraries/System.Linq.Expressions/tests/TypeBinary/TypeIs.cs b/src/libraries/System.Linq.Expressions/tests/TypeBinary/TypeIs.cs
index 26edcd31eff7e6..f789d71f3b0f40 100644
--- a/src/libraries/System.Linq.Expressions/tests/TypeBinary/TypeIs.cs
+++ b/src/libraries/System.Linq.Expressions/tests/TypeBinary/TypeIs.cs
@@ -57,6 +57,7 @@ public void CannotReduce()
 
         [Theory]
         [MemberData(nameof(ExpressionAndTypeCombinations))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public void TypePropertyMatches(Expression expression, Type type)
         {
             Assert.Equal(type, Expression.TypeIs(expression, type).TypeOperand);
diff --git a/src/libraries/System.Linq.Expressions/tests/Unary/UnaryConvertTests.cs b/src/libraries/System.Linq.Expressions/tests/Unary/UnaryConvertTests.cs
index d0b82224e6734e..4cf5c45f2df9a3 100644
--- a/src/libraries/System.Linq.Expressions/tests/Unary/UnaryConvertTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Unary/UnaryConvertTests.cs
@@ -57,6 +57,7 @@ public static void CheckUnaryConvertBooleanToNumericTest(bool useInterpreter)
         }
 
         [Theory, ClassData(typeof(CompilationTypes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public static void ConvertNullToNonNullableValueTest(bool useInterpreter)
         {
             foreach (var e in ConvertNullToNonNullableValue())
diff --git a/src/libraries/System.Linq.Expressions/tests/Unary/UnaryUnboxTests.cs b/src/libraries/System.Linq.Expressions/tests/Unary/UnaryUnboxTests.cs
index 2ec61247eab7fd..184828d0ff46b5 100644
--- a/src/libraries/System.Linq.Expressions/tests/Unary/UnaryUnboxTests.cs
+++ b/src/libraries/System.Linq.Expressions/tests/Unary/UnaryUnboxTests.cs
@@ -10,6 +10,7 @@ public static class UnaryUnboxTests
         #region Test methods
 
         [Theory, ClassData(typeof(CompilationTypes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51952", TestPlatforms.tvOS)]
         public static void CheckUnaryUnboxTest(bool useInterpreter)
         {
             VerifyUnbox(42, typeof(int), false, useInterpreter);
diff --git a/src/libraries/System.Memory/tests/MemoryMarshal/GetArrayDataReference.cs b/src/libraries/System.Memory/tests/MemoryMarshal/GetArrayDataReference.cs
index a421cfdb61006a..5652d275f90cc7 100644
--- a/src/libraries/System.Memory/tests/MemoryMarshal/GetArrayDataReference.cs
+++ b/src/libraries/System.Memory/tests/MemoryMarshal/GetArrayDataReference.cs
@@ -10,6 +10,7 @@ namespace System.SpanTests
     public static partial class MemoryMarshalTests
     {
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36885", TestPlatforms.tvOS)]
         public static void GetArrayDataReference_NullInput_ThrowsNullRef()
         {
             Assert.Throws<NullReferenceException>(() => MemoryMarshal.GetArrayDataReference((object[])null));
diff --git a/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostByNameTest.cs b/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostByNameTest.cs
index 12b95e5cd95aa0..94dba8bdb7fcdc 100644
--- a/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostByNameTest.cs
+++ b/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostByNameTest.cs
@@ -103,6 +103,7 @@ public void DnsObsoleteGetHostByName_IPv6String_ReturnsOnlyGivenIP()
 
         [ActiveIssue("https://github.com/dotnet/runtime/issues/1488", TestPlatforms.OSX)]
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotArm64Process))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/27622")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51377", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DnsObsoleteGetHostByName_EmptyString_ReturnsHostName()
         {
             IPHostEntry entry = Dns.GetHostByName("");
@@ -113,6 +114,7 @@ public void DnsObsoleteGetHostByName_EmptyString_ReturnsHostName()
 
         [ActiveIssue("https://github.com/dotnet/runtime/issues/1488", TestPlatforms.OSX)]
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotArm64Process), nameof(PlatformDetection.IsThreadingSupported))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/27622")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51377", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DnsObsoleteBeginEndGetHostByName_EmptyString_ReturnsHostName()
         {
             IPHostEntry entry = Dns.EndGetHostByName(Dns.BeginGetHostByName("", null, null));
diff --git a/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostEntryTest.cs b/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostEntryTest.cs
index 3c4dd19ea81b4b..6fa40dd80c46a0 100644
--- a/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostEntryTest.cs
+++ b/src/libraries/System.Net.NameResolution/tests/FunctionalTests/GetHostEntryTest.cs
@@ -25,6 +25,7 @@ public async Task Dns_GetHostEntryAsync_IPAddress_Ok()
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsNotArm64Process))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/27622")]
         [InlineData("")]
         [InlineData(TestSettings.LocalHost)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51377", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Dns_GetHostEntry_HostString_Ok(string hostName)
         {
             try
@@ -74,6 +75,7 @@ public async Task Dns_GetHostEntry_HostString_Ok(string hostName)
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsNotArm64Process))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/27622")]
         [InlineData("")]
         [InlineData(TestSettings.LocalHost)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51377", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Dns_GetHostEntryAsync_HostString_Ok(string hostName) =>
             await TestGetHostEntryAsync(() => Dns.GetHostEntryAsync(hostName));
 
diff --git a/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/IPGlobalPropertiesTest.cs b/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/IPGlobalPropertiesTest.cs
index 260f202907ab3d..62ba2328c65b77 100644
--- a/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/IPGlobalPropertiesTest.cs
+++ b/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/IPGlobalPropertiesTest.cs
@@ -26,6 +26,7 @@ public IPGlobalPropertiesTest(ITestOutputHelper output)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36890", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IPGlobalProperties_AccessAllMethods_NoErrors()
         {
             IPGlobalProperties gp = IPGlobalProperties.GetIPGlobalProperties();
@@ -51,6 +52,7 @@ public void IPGlobalProperties_AccessAllMethods_NoErrors()
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
         [MemberData(nameof(Loopbacks))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36890", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IPGlobalProperties_TcpListeners_Succeed(IPAddress address)
         {
             using (var server = new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp))
@@ -76,6 +78,7 @@ public void IPGlobalProperties_TcpListeners_Succeed(IPAddress address)
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34690", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36890", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         [MemberData(nameof(Loopbacks))]
         public async Task IPGlobalProperties_TcpActiveConnections_Succeed(IPAddress address)
         {
diff --git a/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/NetworkInterfaceBasicTest.cs b/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/NetworkInterfaceBasicTest.cs
index 5ea4e0241c4604..2ce80187032907 100644
--- a/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/NetworkInterfaceBasicTest.cs
+++ b/src/libraries/System.Net.NetworkInformation/tests/FunctionalTests/NetworkInterfaceBasicTest.cs
@@ -273,6 +273,7 @@ public void BasicTest_GetIPInterfaceStatistics_Success_Bsd()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // https://github.com/dotnet/runtime/issues/20029 and https://github.com/Microsoft/WSL/issues/3561
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50567", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36890", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void BasicTest_GetIsNetworkAvailable_Success()
         {
             Assert.True(NetworkInterface.GetIsNetworkAvailable());
@@ -281,6 +282,7 @@ public void BasicTest_GetIsNetworkAvailable_Success()
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34690", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "Expected behavior is different on OSX or FreeBSD")]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
         [InlineData(false)]
         [InlineData(true)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50567", TestPlatforms.Android)]
diff --git a/src/libraries/System.Net.Ping/tests/FunctionalTests/PingTest.cs b/src/libraries/System.Net.Ping/tests/FunctionalTests/PingTest.cs
index 5e90cd2512c3e4..74f14a279d395b 100644
--- a/src/libraries/System.Net.Ping/tests/FunctionalTests/PingTest.cs
+++ b/src/libraries/System.Net.Ping/tests/FunctionalTests/PingTest.cs
@@ -125,6 +125,7 @@ public async Task SendPingAsync_InvalidArgs()
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithIPAddress(AddressFamily addressFamily)
         {
             IPAddress localIpAddress = TestSettings.GetLocalIPAddress(addressFamily);
@@ -145,6 +146,7 @@ public void SendPingWithIPAddress(AddressFamily addressFamily)
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithIPAddress(AddressFamily addressFamily)
         {
             IPAddress localIpAddress = await TestSettings.GetLocalIPAddressAsync(addressFamily);
@@ -166,6 +168,7 @@ await SendBatchPingAsync(
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithIPAddress_AddressAsString(AddressFamily addressFamily)
         {
             IPAddress localIpAddress = TestSettings.GetLocalIPAddress(addressFamily);
@@ -184,6 +187,7 @@ public void SendPingWithIPAddress_AddressAsString(AddressFamily addressFamily)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithIPAddress_AddressAsString()
         {
             IPAddress localIpAddress = await TestSettings.GetLocalIPAddressAsync();
@@ -198,6 +202,7 @@ await SendBatchPingAsync(
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithIPAddressAndTimeout()
         {
             IPAddress localIpAddress = TestSettings.GetLocalIPAddress();
@@ -211,6 +216,7 @@ public void SendPingWithIPAddressAndTimeout()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithIPAddressAndTimeout()
         {
             IPAddress localIpAddress = await TestSettings.GetLocalIPAddressAsync();
@@ -258,6 +264,7 @@ await SendBatchPingAsync(
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithIPAddressAndTimeoutAndBuffer_Unix()
         {
             byte[] buffer = TestSettings.PayloadAsBytes;
@@ -283,6 +290,7 @@ public void SendPingWithIPAddressAndTimeoutAndBuffer_Unix()
 
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithIPAddressAndTimeoutAndBuffer_Unix()
         {
             byte[] buffer = TestSettings.PayloadAsBytes;
@@ -347,6 +355,7 @@ await SendBatchPingAsync(
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithIPAddressAndTimeoutAndBufferAndPingOptions_Unix(AddressFamily addressFamily)
         {
             IPAddress localIpAddress = TestSettings.GetLocalIPAddress(addressFamily);
@@ -379,6 +388,7 @@ public void SendPingWithIPAddressAndTimeoutAndBufferAndPingOptions_Unix(AddressF
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithIPAddressAndTimeoutAndBufferAndPingOptions_Unix(AddressFamily addressFamily)
         {
             IPAddress localIpAddress = await TestSettings.GetLocalIPAddressAsync(addressFamily);
@@ -409,6 +419,7 @@ await SendBatchPingAsync(
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithHost()
         {
             IPAddress[] localIpAddresses = TestSettings.GetLocalIPAddresses();
@@ -422,6 +433,7 @@ public void SendPingWithHost()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithHost()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -436,6 +448,7 @@ await SendBatchPingAsync(
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithHostAndTimeout()
         {
             IPAddress[] localIpAddresses = TestSettings.GetLocalIPAddresses();
@@ -449,6 +462,7 @@ public void SendPingWithHostAndTimeout()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithHostAndTimeout()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -496,6 +510,7 @@ await SendBatchPingAsync(
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithHostAndTimeoutAndBuffer_Unix()
         {
             IPAddress[] localIpAddresses = TestSettings.GetLocalIPAddresses();
@@ -521,6 +536,7 @@ public void SendPingWithHostAndTimeoutAndBuffer_Unix()
 
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithHostAndTimeoutAndBuffer_Unix()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -581,6 +597,7 @@ await SendBatchPingAsync(
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SendPingWithHostAndTimeoutAndBufferAndPingOptions_Unix()
         {
             IPAddress[] localIpAddresses = TestSettings.GetLocalIPAddresses();
@@ -606,6 +623,7 @@ public void SendPingWithHostAndTimeoutAndBufferAndPingOptions_Unix()
 
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // On Unix, Non-root pings cannot send arbitrary data in the buffer, and do not receive it back in the PingReply.
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithHostAndTimeoutAndBufferAndPingOptions_Unix()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -630,6 +648,7 @@ await SendBatchPingAsync(
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPings_ReuseInstance_Hostname()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -646,6 +665,7 @@ public async Task SendPings_ReuseInstance_Hostname()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50574", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Sends_ReuseInstance_Hostname()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -661,6 +681,7 @@ public async Task Sends_ReuseInstance_Hostname()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendAsyncs_ReuseInstance_Hostname()
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
@@ -711,6 +732,7 @@ public async Task SendAsyncs_ReuseInstance_Hostname()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void Ping_DisposeAfterSend_Success()
         {
             Ping p = new Ping();
@@ -719,6 +741,7 @@ public static void Ping_DisposeAfterSend_Success()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static async Task PingAsync_DisposeAfterSend_Success()
         {
             Ping p = new Ping();
@@ -795,6 +818,7 @@ public void CanBeFinalized()
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52617", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendPingAsyncWithHostAndTtlAndFragmentPingOptions(bool fragment)
         {
             IPAddress[] localIpAddresses = await TestSettings.GetLocalIPAddressesAsync();
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
index 230495629c4173..e49dd44cc8ce16 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/CreateSocketTests.cs
@@ -274,6 +274,7 @@ public void Ctor_Socket_FromPipeHandle_Ctor_Dispose_Success(bool ownsHandle)
         [InlineData(AddressFamily.InterNetworkV6, SocketType.Raw, ProtocolType.Unspecified)]
         [InlineData(AddressFamily.Packet, SocketType.Raw, ProtocolType.Raw)]
         [InlineData(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Ctor_SafeHandle_BasicPropertiesPropagate_Success(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType)
         {
             bool isRawPacket = (addressFamily == AddressFamily.Packet) &&
@@ -384,6 +385,7 @@ public void Ctor_SafeHandle_BasicPropertiesPropagate_Success(AddressFamily addre
         [Theory]
         [InlineData(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)]
         [InlineData(AddressFamily.InterNetworkV6, SocketType.Stream, ProtocolType.Tcp)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Ctor_SafeHandle_Tcp_SendReceive_Success(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType)
         {
             using var orig = new Socket(addressFamily, socketType, protocolType);
@@ -443,6 +445,7 @@ public async Task Ctor_SafeHandle_Tcp_SendReceive_Success(AddressFamily addressF
         [Theory]
         [InlineData(false)]
         [InlineData(true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Ctor_SafeHandle_Listening_Success(bool shareSafeHandle)
         {
             using var listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
@@ -652,6 +655,7 @@ private static unsafe (int, int) pipe2(int flags = 0)
 
         [Fact]
         [PlatformSpecific(TestPlatforms.AnyUnix)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public unsafe void Ctor_SafeHandle_SocketPair_Success()
         {
             // This is platform dependent but it seems like this is same on all supported platforms.
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
index b8d7d619f31153..600ae16628985e 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs
@@ -354,6 +354,7 @@ public void Socket_BeginConnectV4IPAddressToV4Host_Throws()
         public Task BeginConnectV4IPAddressToV4Host_Success() => DualModeBeginConnect_IPAddressToHost_Helper(IPAddress.Loopback, IPAddress.Loopback, false);
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public Task BeginConnectV6IPAddressToV6Host_Success() => DualModeBeginConnect_IPAddressToHost_Helper(IPAddress.IPv6Loopback, IPAddress.IPv6Loopback, false);
 
         [Fact]
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ExecutionContextFlowTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ExecutionContextFlowTest.cs
index 52996e5bf33d4a..4a020d921adde1 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ExecutionContextFlowTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ExecutionContextFlowTest.cs
@@ -454,6 +454,7 @@ public async Task APM_ExecutionContextFlowsAcrossBeginSendOperation(bool suppres
         [Theory]
         [InlineData(false)]
         [InlineData(true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS)]
         public async Task APM_ExecutionContextFlowsAcrossBeginSendFileOperation(bool suppressContext)
         {
             using (var listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveFrom.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveFrom.cs
index f35808386faae4..efac4a735b74f3 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveFrom.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveFrom.cs
@@ -88,7 +88,7 @@ public async Task NotBound_Throws_InvalidOperationException()
         [InlineData(true)]
         public async Task ReceiveSent_TCP_Success(bool ipv6)
         {
-            if (ipv6 && PlatformDetection.IsOSX)
+            if (ipv6 && PlatformDetection.IsOSXLike)
             {
                 // [ActiveIssue("https://github.com/dotnet/runtime/issues/47335")]
                 // accept() will create a (seemingly) DualMode socket on Mac,
@@ -170,6 +170,7 @@ public async Task ClosedBeforeOperation_Throws_ObjectDisposedException(bool clos
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ClosedDuringOperation_Throws_ObjectDisposedExceptionOrSocketException(bool closeOrDispose)
         {
             if (UsesSync && PlatformDetection.IsOSX)
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveMessageFrom.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveMessageFrom.cs
index eca9145414d1ed..3e792b7bd272b0 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveMessageFrom.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/ReceiveMessageFrom.cs
@@ -89,7 +89,7 @@ public async Task NotBound_Throws_InvalidOperationException()
         [InlineData(true)]
         public async Task ReceiveSent_TCP_Success(bool ipv6)
         {
-            if (ipv6 && PlatformDetection.IsOSX)
+            if (ipv6 && PlatformDetection.IsOSXLike)
             {
                 // [ActiveIssue("https://github.com/dotnet/runtime/issues/47335")]
                 // accept() will create a (seemingly) DualMode socket on Mac,
@@ -174,6 +174,7 @@ public async Task ClosedBeforeOperation_Throws_ObjectDisposedException(bool clos
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ClosedDuringOperation_Throws_ObjectDisposedExceptionOrSocketException(bool closeOrDispose)
         {
             if (UsesSync && PlatformDetection.IsOSX)
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
index 5a7edea1ccd75b..e3187cdc066df0 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
@@ -111,6 +111,7 @@ public void Select_SocketAlreadyClosed_AllSocketsClosableAfterException(int sock
 
         [SkipOnPlatform(TestPlatforms.OSX, "typical OSX install has very low max open file descriptors value")]
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Select_ReadError_NoneReady_ManySockets()
         {
             Select_ReadError_NoneReady(45, 45);
@@ -178,6 +179,7 @@ public void Select_Read_OneReadyAtATime(int reads)
 
         [SkipOnPlatform(TestPlatforms.OSX, "typical OSX install has very low max open file descriptors value")]
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Select_Error_OneReadyAtATime()
         {
             const int Errors = 90; // value larger than the internal value in SocketPal.Unix that swaps between stack and heap allocation
@@ -225,6 +227,7 @@ public void Poll_NotReady(SelectMode mode)
         [Theory]
         [InlineData(-1)]
         [InlineData(FailTimeoutMicroseconds)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Poll_ReadReady_LongTimeouts(int microsecondsTimeout)
         {
             KeyValuePair<Socket, Socket> pair = CreateConnectedSockets();
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
index 478951acd7770b..0a8aaff9970bf3 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
@@ -753,6 +753,7 @@ await Task.WhenAll(
 
         [Fact]
         [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "SendBufferSize, ReceiveBufferSize = 0 not supported on BSD like stacks.")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task SendRecv_NoBuffering_Success()
         {
             if (UsesSync) return;
@@ -931,6 +932,7 @@ error is SocketException ||
         [Theory]
         [MemberData(nameof(UdpReceiveGetsCanceledByDispose_Data))]
         [SkipOnPlatform(TestPlatforms.OSX, "Not supported on OSX.")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task UdpReceiveGetsCanceledByDispose(IPAddress address)
         {
             // We try this a couple of times to deal with a timing race: if the Dispose happens
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
index 9b83b4da3f9590..a504f3957dd3b2 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs
@@ -122,6 +122,7 @@ public void MulticastInterface_Set_InvalidIndex_Throws()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsNanoNorServerCore))] // Skip on Nano: https://github.com/dotnet/runtime/issues/26286
         [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "Expected behavior is different on OSX or FreeBSD")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task MulticastInterface_Set_IPv6_AnyInterface_Succeeds()
         {
             if (PlatformDetection.IsRedHatFamily7)
@@ -507,6 +508,7 @@ public void SetIPProtectionLevel_ArgumentException(AddressFamily family)
         [InlineData(AddressFamily.InterNetwork)]
         [InlineData(AddressFamily.InterNetworkV6)]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50568", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetSetRawSocketOption_Roundtrips(AddressFamily family)
         {
             int SOL_SOCKET;
@@ -546,6 +548,7 @@ public void GetSetRawSocketOption_Roundtrips(AddressFamily family)
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Get_AcceptConnection_Succeeds()
         {
             using (Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/TcpListenerTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/TcpListenerTest.cs
index e442a33ade7e20..c7311ddba69ba6 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/TcpListenerTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/TcpListenerTest.cs
@@ -128,6 +128,7 @@ public void Accept_Invalid_Throws()
         [InlineData(0)] // Sync
         [InlineData(1)] // Async
         [InlineData(2)] // APM
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Accept_AcceptsPendingSocketOrClient(int mode)
         {
             var listener = new TcpListener(IPAddress.Loopback, 0);
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UdpClientTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UdpClientTest.cs
index b639f88d8f6385..1137613a062c18 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UdpClientTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UdpClientTest.cs
@@ -257,6 +257,7 @@ public void Ttl_Roundtrips()
 
         [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "BSD like doesn't have an equivalent of DontFragment")]
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DontFragment_Roundtrips()
         {
             using (var udpClient = new UdpClient())
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
index 7b155639807cea..35486516aec121 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/UnixDomainSocketTest.cs
@@ -29,6 +29,7 @@ public void OSSupportsUnixDomainSockets_ReturnsCorrectValue()
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Socket_ConnectAsyncUnixDomainSocketEndPoint_Success()
         {
             string path = null;
@@ -84,6 +85,7 @@ public async Task Socket_ConnectAsyncUnixDomainSocketEndPoint_Success()
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Socket_ConnectAsyncUnixDomainSocketEndPoint_NotServer()
         {
             string path = GetRandomNonExistingFilePath();
@@ -118,6 +120,7 @@ public async Task Socket_ConnectAsyncUnixDomainSocketEndPoint_NotServer()
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Socket_SendReceive_Success()
         {
             string path = GetRandomNonExistingFilePath();
@@ -155,6 +158,7 @@ public void Socket_SendReceive_Success()
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Socket_SendReceive_Clone_Success()
         {
             string path = GetRandomNonExistingFilePath();
@@ -205,6 +209,7 @@ public void Socket_SendReceive_Clone_Success()
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Socket_SendReceiveAsync_Success()
         {
             string path = GetRandomNonExistingFilePath();
@@ -247,6 +252,7 @@ public async Task Socket_SendReceiveAsync_Success()
         [InlineData(500, 18, 21)]
         [InlineData(500, 21, 18)]
         [InlineData(5, 128000, 64000)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task Socket_SendReceiveAsync_PropagateToStream_Success(int iterations, int writeBufferSize, int readBufferSize)
         {
             var writeBuffer = new byte[writeBufferSize * iterations];
@@ -308,6 +314,7 @@ public async Task Socket_SendReceiveAsync_PropagateToStream_Success(int iteratio
         [ActiveIssue("https://github.com/dotnet/runtime/issues/26189", TestPlatforms.Windows)]
         [InlineData(false)]
         [InlineData(true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ConcurrentSendReceive(bool forceNonBlocking)
         {
             using (Socket server = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified))
@@ -350,6 +357,7 @@ public async Task ConcurrentSendReceive(bool forceNonBlocking)
         }
 
         [ConditionalFact(nameof(PlatformSupportsUnixDomainSockets))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public async Task ConcurrentSendReceiveAsync()
         {
             using (Socket server = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified))
@@ -404,6 +412,7 @@ public void UnixDomainSocketEndPoint_InvalidPaths_Throws()
         [ConditionalTheory(nameof(PlatformSupportsUnixDomainSockets))]
         [InlineData(false)]
         [InlineData(true)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51392", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void UnixDomainSocketEndPoint_RemoteEndPointEqualsBindAddress(bool abstractAddress)
         {
             string serverAddress;
diff --git a/src/libraries/System.Private.Xml/tests/XmlReader/Tests/AsyncReaderLateInitTests.cs b/src/libraries/System.Private.Xml/tests/XmlReader/Tests/AsyncReaderLateInitTests.cs
index a7757ba4999541..482014481e8fb4 100644
--- a/src/libraries/System.Private.Xml/tests/XmlReader/Tests/AsyncReaderLateInitTests.cs
+++ b/src/libraries/System.Private.Xml/tests/XmlReader/Tests/AsyncReaderLateInitTests.cs
@@ -69,7 +69,6 @@ public static void ReadAfterInitializationWithTextReaderOnAsyncReaderDoesNotThro
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/49187", TestPlatforms.iOS | TestPlatforms.MacCatalyst | TestPlatforms.tvOS)]
         public static void ReadAsyncAfterInitializationWithUriThrows()
         {
             using (XmlReader reader = XmlReader.Create("http://test.test/test.html", new XmlReaderSettings() { Async = true }))
@@ -79,7 +78,6 @@ public static void ReadAsyncAfterInitializationWithUriThrows()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/49187", TestPlatforms.iOS | TestPlatforms.MacCatalyst | TestPlatforms.tvOS)]
         public static void ReadAfterInitializationWithUriOnAsyncReaderTrows()
         {
             using (XmlReader reader = XmlReader.Create("http://test.test/test.html", new XmlReaderSettings() { Async = true }))
@@ -89,7 +87,6 @@ public static void ReadAfterInitializationWithUriOnAsyncReaderTrows()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsSubsystemForLinux), nameof(PlatformDetection.IsThreadingSupported))] // [ActiveIssue("https://github.com/dotnet/runtime/issues/18258")]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/49187", TestPlatforms.iOS | TestPlatforms.MacCatalyst | TestPlatforms.tvOS)]
         public static void InitializationWithUriOnNonAsyncReaderThrows()
         {
             Assert.Throws<System.Net.Http.HttpRequestException>(() => XmlReader.Create("http://test.test/test.html", new XmlReaderSettings() { Async = false }));
diff --git a/src/libraries/System.Reflection/tests/AssemblyTests.cs b/src/libraries/System.Reflection/tests/AssemblyTests.cs
index 43af72686e7b61..0732615ec9e02e 100644
--- a/src/libraries/System.Reflection/tests/AssemblyTests.cs
+++ b/src/libraries/System.Reflection/tests/AssemblyTests.cs
@@ -145,6 +145,7 @@ public void ExportedTypes(Type type, bool expected)
 
         [Fact]
         [SkipOnPlatform(TestPlatforms.Browser, "entry assembly won't be xunit.console on browser")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36892", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetEntryAssembly()
         {
             Assert.NotNull(Assembly.GetEntryAssembly());
@@ -719,6 +720,7 @@ public void AssemblyLoadFromBytesNeg()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36892", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void AssemblyLoadFromBytesWithSymbols()
         {
             Assembly assembly = typeof(AssemblyTests).Assembly;
diff --git a/src/libraries/System.Resources.ResourceManager/tests/ResourceManagerTests.cs b/src/libraries/System.Resources.ResourceManager/tests/ResourceManagerTests.cs
index a7ab855896769a..ce3dd68df7e41c 100644
--- a/src/libraries/System.Resources.ResourceManager/tests/ResourceManagerTests.cs
+++ b/src/libraries/System.Resources.ResourceManager/tests/ResourceManagerTests.cs
@@ -82,6 +82,7 @@ public static IEnumerable<object[]> CultureResourceData()
 
         [Theory]
         [MemberData(nameof(CultureResourceData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36893", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void GetString_CultureFallback(string key, string cultureName, string expectedValue)
         {
             Type resourceType = typeof(Resources.TestResx);
@@ -92,6 +93,7 @@ public static void GetString_CultureFallback(string key, string cultureName, str
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36893", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void GetString_FromTestClassWithoutNeutralResources()
         {
             // This test is designed to complement the GetString_FromCulutureAndResourceType "fr" & "fr-CA" cases
diff --git a/src/libraries/System.Runtime.Extensions/tests/System/AppDomainTests.cs b/src/libraries/System.Runtime.Extensions/tests/System/AppDomainTests.cs
index 449b8c7f040e82..098a8519786356 100644
--- a/src/libraries/System.Runtime.Extensions/tests/System/AppDomainTests.cs
+++ b/src/libraries/System.Runtime.Extensions/tests/System/AppDomainTests.cs
@@ -47,6 +47,7 @@ public void RelativeSearchPath_Is_Null()
         [SkipOnPlatform(TestPlatforms.Browser, "throws pNSE")]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49568", typeof(PlatformDetection), nameof(PlatformDetection.IsMacOsAppleSilicon))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49868", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TargetFrameworkTest()
         {
             const int ExpectedExitCode = 0;
@@ -797,6 +798,7 @@ public static void GetPermissionSet()
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34030", TestPlatforms.Linux | TestPlatforms.Browser | TestPlatforms.Android, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [MemberData(nameof(TestingCreateInstanceFromObjectHandleData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TestingCreateInstanceFromObjectHandle(string physicalFileName, string assemblyFile, string type, string returnedFullNameType, Type exceptionType)
         {
             ObjectHandle oh = null;
@@ -897,6 +899,7 @@ public static void TestingCreateInstanceObjectHandle(string assemblyName, string
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34030", TestPlatforms.Linux | TestPlatforms.Browser | TestPlatforms.Android, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [MemberData(nameof(TestingCreateInstanceFromObjectHandleFullSignatureData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TestingCreateInstanceFromObjectHandleFullSignature(string physicalFileName, string assemblyFile, string type, bool ignoreCase, BindingFlags bindingAttr, Binder binder, object[] args, CultureInfo culture, object[] activationAttributes, string returnedFullNameType)
         {
             ObjectHandle oh = AppDomain.CurrentDomain.CreateInstanceFrom(assemblyFile: assemblyFile, typeName: type, ignoreCase: ignoreCase, bindingAttr: bindingAttr, binder: binder, args: args, culture: culture, activationAttributes: activationAttributes);
diff --git a/src/libraries/System.Runtime.Extensions/tests/System/Environment.Exit.cs b/src/libraries/System.Runtime.Extensions/tests/System/Environment.Exit.cs
index 8ca85743f417c9..0ad14d628fc745 100644
--- a/src/libraries/System.Runtime.Extensions/tests/System/Environment.Exit.cs
+++ b/src/libraries/System.Runtime.Extensions/tests/System/Environment.Exit.cs
@@ -42,7 +42,7 @@ public static void ExitCode_Roundtrips(int exitCode)
         [InlineData(1)] // setting ExitCode and exiting Main
         [InlineData(2)] // setting ExitCode both from Main and from an Unloading event handler.
         [InlineData(3)] // using Exit(exitCode)
-        [SkipOnPlatform(TestPlatforms.Browser, "throws PNSE")]
+        [SkipOnPlatform(TestPlatforms.Browser | TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on Browser, iOS, or tvOS.")]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49568", typeof(PlatformDetection), nameof(PlatformDetection.IsMacOsAppleSilicon))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49868", TestPlatforms.Android)]
         public static void ExitCode_VoidMainAppReturnsSetValue(int mode)
diff --git a/src/libraries/System.Runtime.Extensions/tests/System/Environment.UserName.cs b/src/libraries/System.Runtime.Extensions/tests/System/Environment.UserName.cs
index 2157f63c0250a0..adc427746ee289 100644
--- a/src/libraries/System.Runtime.Extensions/tests/System/Environment.UserName.cs
+++ b/src/libraries/System.Runtime.Extensions/tests/System/Environment.UserName.cs
@@ -22,6 +22,7 @@ public void UserNameIsCorrect()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS)]
         public void UserName_Valid()
         {
             string name = Environment.UserName;
diff --git a/src/libraries/System.Runtime.Extensions/tests/System/EnvironmentTests.cs b/src/libraries/System.Runtime.Extensions/tests/System/EnvironmentTests.cs
index f027d6859a8172..b192b0900acd03 100644
--- a/src/libraries/System.Runtime.Extensions/tests/System/EnvironmentTests.cs
+++ b/src/libraries/System.Runtime.Extensions/tests/System/EnvironmentTests.cs
@@ -173,6 +173,7 @@ public void OSVersion_ValidVersion()
         [InlineData("nelknet 4.15.0-24201807041620-generic", 4, 15, 0, int.MaxValue)] // integer overflow
         [InlineData("", 0, 0, 0, 0)]
         [InlineData("1abc", 1, 0, 0, 0)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void OSVersion_ParseVersion(string input, int major, int minor, int build, int revision)
         {
             var getOSMethod = typeof(Environment).GetMethod("GetOperatingSystem", BindingFlags.Static | BindingFlags.NonPublic);
@@ -337,6 +338,7 @@ public void FailFast_ExceptionStackTrace_InnerException()
 
         [Fact]
         [PlatformSpecific(TestPlatforms.AnyUnix | TestPlatforms.Browser)]  // Tests OS-specific environment
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36896", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetFolderPath_Unix_PersonalIsHomeAndUserProfile()
         {
             Assert.Equal(Environment.GetEnvironmentVariable("HOME"), Environment.GetFolderPath(Environment.SpecialFolder.Personal));
diff --git a/src/libraries/System.Runtime/tests/System/ActivatorTests.cs b/src/libraries/System.Runtime/tests/System/ActivatorTests.cs
index 4751c15dcdad1e..0ff08745c844c5 100644
--- a/src/libraries/System.Runtime/tests/System/ActivatorTests.cs
+++ b/src/libraries/System.Runtime/tests/System/ActivatorTests.cs
@@ -621,6 +621,7 @@ public void CreateInstance_PublicOnlyValueTypeWithPrivateDefaultConstructor_Thro
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34030", TestPlatforms.Linux | TestPlatforms.Browser, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [MemberData(nameof(TestingCreateInstanceFromObjectHandleData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TestingCreateInstanceFromObjectHandle(string physicalFileName, string assemblyFile, string type, string returnedFullNameType, Type exceptionType)
         {
             ObjectHandle oh = null;
@@ -663,6 +664,7 @@ public static void TestingCreateInstanceFromObjectHandle(string physicalFileName
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/51912", typeof(PlatformDetection), nameof(PlatformDetection.IsBuiltWithAggressiveTrimming), nameof(PlatformDetection.IsBrowser))]
         [MemberData(nameof(TestingCreateInstanceObjectHandleData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TestingCreateInstanceObjectHandle(string assemblyName, string type, string returnedFullNameType, Type exceptionType, bool returnNull)
         {
             ObjectHandle oh = null;
@@ -720,6 +722,7 @@ public static void TestingCreateInstanceObjectHandle(string assemblyName, string
         [Theory]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34030", TestPlatforms.Linux | TestPlatforms.Browser, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
         [MemberData(nameof(TestingCreateInstanceFromObjectHandleFullSignatureData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TestingCreateInstanceFromObjectHandleFullSignature(string physicalFileName, string assemblyFile, string type, bool ignoreCase, BindingFlags bindingAttr, Binder binder, object[] args, CultureInfo culture, object[] activationAttributes, string returnedFullNameType)
         {
             ObjectHandle oh = Activator.CreateInstanceFrom(assemblyFile: assemblyFile, typeName: type, ignoreCase: ignoreCase, bindingAttr: bindingAttr, binder: binder, args: args, culture: culture, activationAttributes: activationAttributes);
diff --git a/src/libraries/System.Runtime/tests/System/Reflection/ModuleTests.cs b/src/libraries/System.Runtime/tests/System/Reflection/ModuleTests.cs
index 851317583e4f10..a481ee253a55e4 100644
--- a/src/libraries/System.Runtime/tests/System/Reflection/ModuleTests.cs
+++ b/src/libraries/System.Runtime/tests/System/Reflection/ModuleTests.cs
@@ -303,6 +303,7 @@ public void ResolveMethodFail(int token)
 
         [Theory]
         [MemberData(nameof(Fields))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ResolveField(FieldInfo t)
         {
             Assert.Equal(t, Module.ResolveField(t.MetadataToken));
diff --git a/src/libraries/System.Runtime/tests/System/TimeZoneInfoTests.cs b/src/libraries/System.Runtime/tests/System/TimeZoneInfoTests.cs
index 3b72bf0bdf8a53..3167476689f0ea 100644
--- a/src/libraries/System.Runtime/tests/System/TimeZoneInfoTests.cs
+++ b/src/libraries/System.Runtime/tests/System/TimeZoneInfoTests.cs
@@ -124,6 +124,7 @@ public static IEnumerable<object []> Platform_TimeZoneNamesTestData()
         // We test the existence of a specific English time zone name to avoid failures on non-English platforms.
         [ConditionalTheory(nameof(IsEnglishUILanguage))]
         [MemberData(nameof(Platform_TimeZoneNamesTestData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void Platform_TimeZoneNames(TimeZoneInfo tzi, string displayName, string standardName, string daylightName)
         {
             // Edge case - Optionally allow some characters to be absent in the display name.
@@ -2621,6 +2622,7 @@ public static void EnsureUtcObjectSingleton()
         [InlineData("Argentina Standard Time", "America/Argentina/Catamarca")]
         [InlineData("Newfoundland Standard Time", "America/St_Johns")]
         [InlineData("Iran Standard Time", "Asia/Tehran")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void UsingAlternativeTimeZoneIdsTest(string windowsId, string ianaId)
         {
             if (PlatformDetection.ICUVersion.Major >= 52)
@@ -2641,6 +2643,7 @@ public static void UsingAlternativeTimeZoneIdsTest(string windowsId, string iana
         public static bool SupportIanaNamesConversion => PlatformDetection.IsNotBrowser && PlatformDetection.ICUVersion.Major >= 52;
 
         [ConditionalFact(nameof(SupportIanaNamesConversion))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void IsIanaIdTest()
         {
             bool expected = !s_isWindows;
@@ -2670,6 +2673,7 @@ public static void IsIanaIdTest()
         [InlineData("Argentina Standard Time", "America/Buenos_Aires")]
         [InlineData("Newfoundland Standard Time", "America/St_Johns")]
         [InlineData("Iran Standard Time", "Asia/Tehran")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void IdsConversionsTest(string windowsId, string ianaId)
         {
             Assert.True(TimeZoneInfo.TryConvertIanaIdToWindowsId(ianaId, out string winId));
@@ -2691,6 +2695,7 @@ public static void IdsConversionsTest(string windowsId, string ianaId)
         [InlineData("Central Europe Standard Time", "Europe/Tirane", "AL")]
         [InlineData("Central Europe Standard Time", "Europe/Podgorica", "ME")]
         [InlineData("Central Europe Standard Time", "Europe/Belgrade", "RS")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void IdsConversionsWithRegionTest(string windowsId, string ianaId, string region)
         {
             Assert.True(TimeZoneInfo.TryConvertWindowsIdToIanaId(windowsId, region, out string ianaConvertedId));
diff --git a/src/libraries/System.Runtime/tests/System/Type/TypeTests.cs b/src/libraries/System.Runtime/tests/System/Type/TypeTests.cs
index a7e21552fcd615..1464db6d4e8244 100644
--- a/src/libraries/System.Runtime/tests/System/Type/TypeTests.cs
+++ b/src/libraries/System.Runtime/tests/System/Type/TypeTests.cs
@@ -248,6 +248,7 @@ public static IEnumerable<object[]> MakeArray_UnusualTypes_TestData()
 
         [Theory]
         [MemberData(nameof(MakeArray_UnusualTypes_TestData))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void MakeArrayType_UnusualTypes_ReturnsExpected(Type t)
         {
             Type tArray = t.MakeArrayType();
@@ -587,6 +588,7 @@ public void IsSZArray_FalseForNonArrayTypes()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IsSZArray_TrueForSZArrayTypes()
         {
             foreach (Type type in NonArrayBaseTypes.Select(nonArrayBaseType => nonArrayBaseType.MakeArrayType()))
@@ -638,6 +640,7 @@ public void IsVariableBoundArray_FalseForNonArrayTypes()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52072", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IsVariableBoundArray_FalseForSZArrayTypes()
         {
             foreach (Type type in NonArrayBaseTypes.Select(nonArrayBaseType => nonArrayBaseType.MakeArrayType()))
diff --git a/src/libraries/System.Security.Cryptography.Algorithms/tests/AesCcmTests.cs b/src/libraries/System.Security.Cryptography.Algorithms/tests/AesCcmTests.cs
index 6f5f77aa501849..149b28da9e32dd 100644
--- a/src/libraries/System.Security.Cryptography.Algorithms/tests/AesCcmTests.cs
+++ b/src/libraries/System.Security.Cryptography.Algorithms/tests/AesCcmTests.cs
@@ -12,6 +12,7 @@ namespace System.Security.Cryptography.Algorithms.Tests
     public class AesCcmTests : CommonAEADTests
     {
         [Theory]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         [MemberData(nameof(EncryptTamperAADDecryptTestInputs))]
         public static void EncryptTamperAADDecrypt(int dataLength, int additionalDataLength)
         {
@@ -72,6 +73,7 @@ public static void InvalidNonceSize(int nonceSize)
 
         [Theory]
         [MemberData(nameof(GetValidNonceSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ValidNonceSize(int nonceSize)
         {
             const int dataLength = 35;
@@ -114,6 +116,7 @@ public static void InvalidTagSize(int tagSize)
 
         [Theory]
         [MemberData(nameof(GetValidTagSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ValidTagSize(int tagSize)
         {
             const int dataLength = 35;
@@ -136,6 +139,7 @@ public static void ValidTagSize(int tagSize)
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TwoEncryptionsAndDecryptionsUsingOneInstance()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -263,6 +267,7 @@ public static void EncryptDecryptNullTag()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InplaceEncryptDecrypt()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -283,6 +288,7 @@ public static void InplaceEncryptDecrypt()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InplaceEncryptTamperTagDecrypt()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -307,6 +313,7 @@ public static void InplaceEncryptTamperTagDecrypt()
 
         [Theory]
         [MemberData(nameof(GetNistCcmTestCases))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesCcmNistTests(AEADTest testCase)
         {
             using (var aesCcm = new AesCcm(testCase.Key))
@@ -325,6 +332,7 @@ public static void AesCcmNistTests(AEADTest testCase)
 
         [Theory]
         [MemberData(nameof(GetNistCcmTestCases))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesCcmNistTestsTamperTag(AEADTest testCase)
         {
             using (var aesCcm = new AesCcm(testCase.Key))
@@ -347,6 +355,7 @@ public static void AesCcmNistTestsTamperTag(AEADTest testCase)
 
         [Theory]
         [MemberData(nameof(GetNistCcmTestCasesWithNonEmptyPT))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesCcmNistTestsTamperCiphertext(AEADTest testCase)
         {
             using (var aesCcm = new AesCcm(testCase.Key))
diff --git a/src/libraries/System.Security.Cryptography.Algorithms/tests/AesGcmTests.cs b/src/libraries/System.Security.Cryptography.Algorithms/tests/AesGcmTests.cs
index d95482f2c478d8..aafb9ff010e672 100644
--- a/src/libraries/System.Security.Cryptography.Algorithms/tests/AesGcmTests.cs
+++ b/src/libraries/System.Security.Cryptography.Algorithms/tests/AesGcmTests.cs
@@ -12,6 +12,7 @@ namespace System.Security.Cryptography.Algorithms.Tests
     public class AesGcmTests : CommonAEADTests
     {
         [Theory]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         [MemberData(nameof(EncryptTamperAADDecryptTestInputs))]
         public static void EncryptTamperAADDecrypt(int dataLength, int additionalDataLength)
         {
@@ -53,6 +54,7 @@ public static void InvalidKeyLength(int keyLength)
 
         [Theory]
         [MemberData(nameof(GetInvalidNonceSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InvalidNonceSize(int nonceSize)
         {
             int dataLength = 30;
@@ -72,6 +74,7 @@ public static void InvalidNonceSize(int nonceSize)
 
         [Theory]
         [MemberData(nameof(GetValidNonceSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ValidNonceSize(int nonceSize)
         {
             const int dataLength = 35;
@@ -95,6 +98,7 @@ public static void ValidNonceSize(int nonceSize)
 
         [Theory]
         [MemberData(nameof(GetInvalidTagSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InvalidTagSize(int tagSize)
         {
             int dataLength = 30;
@@ -114,6 +118,7 @@ public static void InvalidTagSize(int tagSize)
 
         [Theory]
         [MemberData(nameof(GetValidTagSizes))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ValidTagSize(int tagSize)
         {
             const int dataLength = 35;
@@ -136,6 +141,7 @@ public static void ValidTagSize(int tagSize)
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void TwoEncryptionsAndDecryptionsUsingOneInstance()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -180,6 +186,7 @@ public static void TwoEncryptionsAndDecryptionsUsingOneInstance()
         }
 
         [Theory]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         [MemberData(nameof(PlaintextAndCiphertextSizeDifferTestInputs))]
         public static void PlaintextAndCiphertextSizeDiffer(int ptLen, int ctLen)
         {
@@ -203,6 +210,7 @@ public static void NullKey()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void EncryptDecryptNullNonce()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -218,6 +226,7 @@ public static void EncryptDecryptNullNonce()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void EncryptDecryptNullPlaintext()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -233,6 +242,7 @@ public static void EncryptDecryptNullPlaintext()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void EncryptDecryptNullCiphertext()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -248,6 +258,7 @@ public static void EncryptDecryptNullCiphertext()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void EncryptDecryptNullTag()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -263,6 +274,7 @@ public static void EncryptDecryptNullTag()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InplaceEncryptDecrypt()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -283,6 +295,7 @@ public static void InplaceEncryptDecrypt()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void InplaceEncryptTamperTagDecrypt()
         {
             byte[] key = "d5a194ed90cfe08abecd4691997ceb2c".HexToByteArray();
@@ -307,6 +320,7 @@ public static void InplaceEncryptTamperTagDecrypt()
 
         [Theory]
         [MemberData(nameof(GetNistGcmTestCases))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesGcmNistTests(AEADTest testCase)
         {
             using (var aesGcm = new AesGcm(testCase.Key))
@@ -325,6 +339,7 @@ public static void AesGcmNistTests(AEADTest testCase)
 
         [Theory]
         [MemberData(nameof(GetNistGcmTestCases))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesGcmNistTestsTamperTag(AEADTest testCase)
         {
             using (var aesGcm = new AesGcm(testCase.Key))
@@ -347,6 +362,7 @@ public static void AesGcmNistTestsTamperTag(AEADTest testCase)
 
         [Theory]
         [MemberData(nameof(GetNistGcmTestCasesWithNonEmptyPT))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51332", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AesGcmNistTestsTamperCiphertext(AEADTest testCase)
         {
             using (var aesGcm = new AesGcm(testCase.Key))
diff --git a/src/libraries/System.Security.Cryptography.Csp/tests/DSACryptoServiceProviderTests.cs b/src/libraries/System.Security.Cryptography.Csp/tests/DSACryptoServiceProviderTests.cs
index d2a64c4a96fd89..a766c5fe36688d 100644
--- a/src/libraries/System.Security.Cryptography.Csp/tests/DSACryptoServiceProviderTests.cs
+++ b/src/libraries/System.Security.Cryptography.Csp/tests/DSACryptoServiceProviderTests.cs
@@ -33,6 +33,7 @@ public static void PublicOnly_DefaultKey()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51331", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void PublicOnly_WithPrivateKey()
         {
             using (var dsa = new DSACryptoServiceProvider())
diff --git a/src/libraries/System.Security.Cryptography.Encoding/tests/Oid.cs b/src/libraries/System.Security.Cryptography.Encoding/tests/Oid.cs
index c6453513873a3b..74372351d523ac 100644
--- a/src/libraries/System.Security.Cryptography.Encoding/tests/Oid.cs
+++ b/src/libraries/System.Security.Cryptography.Encoding/tests/Oid.cs
@@ -301,6 +301,7 @@ public static void LookupOidByFriendlyName_Method_BadInput(string badInput)
 
         [Fact]
         [PlatformSpecific(PlatformSupport.OpenSSL)] // Uses P/Invokes to search Oid in the lookup table
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51388", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void LookupOidByValue_Method_OpenSSL()
         {
             // This needs to be an OID not in the static lookup table.  The purpose is to verify the
@@ -314,6 +315,7 @@ public static void LookupOidByValue_Method_OpenSSL()
 
         [Fact]
         [PlatformSpecific(PlatformSupport.OpenSSL)]  // Uses P/Invokes to search Oid in the lookup table
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51388", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void LookupOidByFriendlyName_Method_OpenSSL()
         {
             // This needs to be a name not in the static lookup table.  The purpose is to verify the
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/DSAKeyValueTest.cs b/src/libraries/System.Security.Cryptography.Xml/tests/DSAKeyValueTest.cs
index b0c6ebd780eb8b..a26582120fd2a9 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/DSAKeyValueTest.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/DSAKeyValueTest.cs
@@ -51,6 +51,7 @@ public void Ctor_Dsa_Null()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/20575", TestPlatforms.OSX)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void GetXml()
         {
             DSAKeyValue dsa = new DSAKeyValue();
@@ -79,6 +80,7 @@ public void GetXml()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/20575", TestPlatforms.OSX)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void GetXml_SameDsa()
         {
             using (DSA dsa = DSA.Create())
@@ -90,6 +92,7 @@ public void GetXml_SameDsa()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void LoadXml()
         {
             const string pValue = "oDZlcdJA1Kf6UeNEIZqm4KDqA6zpX7CmEtAGWi9pgnBhWOUDVEfhswfsvTLR5BCbKfE6KoHvt5Hh8D1RcAko//iZkLZ+gds9y/5Oxape8tu3TUi1BnNPWu8ieXjMtdnpyudKFsCymssJked1rBeRePG23HTVwOV1DpopjRkjBEU=";
@@ -129,6 +132,7 @@ public void LoadXml_Null()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void ImportDSAKeyValue()
         {
             string p = "6zJxhRqpk5yQ7sjFSr6mPepyVwpTAXSmw1oh+5Cn/z1DjFSpW6rC6sTOkE3CMNwWOwIzrpVS3bWep7wo9CaBrOPIIVe+E4sqpPeyM2wr10mQThHEsCQAjnxBhJJindf9amaBhi6sOtVNnyETFWV6yKDptZEm9c3xdl4L7ogEbX8=";
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTest.cs b/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTest.cs
index 79b19f77026d34..5e11d908899341 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTest.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTest.cs
@@ -89,6 +89,7 @@ public void Constructor_XmlDocumentAndEvidence()
         [Theory]
         [InlineData("System.Security.Cryptography.Xml.Tests.EncryptedXmlSample1.xml")]
         [InlineData("System.Security.Cryptography.Xml.Tests.EncryptedXmlSample3.xml")]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void RsaDecryption(string resourceName)
         {
             XmlDocument doc = new XmlDocument();
@@ -245,6 +246,7 @@ public void Encrypt_DecryptDocument_AES()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Encrypt_X509()
         {
             XmlDocument doc = new XmlDocument();
@@ -269,6 +271,7 @@ public void Encrypt_X509()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Encrypt_X509_XmlNull()
         {
             using (X509Certificate2 certificate = TestHelpers.GetSampleX509Certificate())
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTests.cs b/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTests.cs
index 286c089a237872..73cccbd9f77806 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTests.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/EncryptedXmlTests.cs
@@ -11,6 +11,8 @@ namespace System.Security.Cryptography.Xml.Tests
     public static class EncryptedXmlTests
     {
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/49871", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void DecryptWithCertificate_NotInStore()
         {
             const string SecretMessage = "Grilled cheese is tasty";
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoTest.cs b/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoTest.cs
index 4951ec10bb04f3..9812572ae6abd7 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoTest.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoTest.cs
@@ -69,6 +69,7 @@ public void KeyInfoNode()
         private static string xmlDSA = "<DSAKeyValue><P>" + dsaP + "</P><Q>" + dsaQ + "</Q><G>" + dsaG + "</G><Y>" + dsaY + "</Y></DSAKeyValue>";
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void DSAKeyValue()
         {
             using (DSA key = DSA.Create())
@@ -132,6 +133,7 @@ public void RetrievalMethod()
             0xD9,0xB2,0xAB,0x8A,0x12,0xB6,0x30,0x78,0x68,0x11,0x7C,0x0D,0xF1,0x49,0x4D,0xA3,0xFD,0xB2,0xE9,0xFF,0x1D,0xF0,0x91,0xFA,0x54,0x85,0xFF,0x33,0x90,0xE8,0xC1,0xBF,0xA4,0x9B,0xA4,0x62,0x46,0xBD,0x61,0x12,0x59,0x98,0x41,0x89 };
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void X509Data()
         {
             using (X509Certificate x509 = new X509Certificate(cert))
@@ -146,6 +148,7 @@ public void X509Data()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void Complex()
         {
             KeyInfoName name = new KeyInfoName();
@@ -196,6 +199,7 @@ public void Complex()
         }
 
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void ImportKeyNode()
         {
             string keyName = "Mono::";
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoX509DataTest.cs b/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoX509DataTest.cs
index 96b75499b732b0..cf3092e87ccba6 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoX509DataTest.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/KeyInfoX509DataTest.cs
@@ -88,6 +88,7 @@ public void Constructor_X509CertificateByteArray_Null()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Constructor_X509Certificate()
         {
             KeyInfoX509Data data1 = new KeyInfoX509Data();
@@ -107,6 +108,7 @@ public void Constructor_X509Certificate()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Constructor_X509Certificate_X509IncludeOption()
         {
             KeyInfoX509Data data = new KeyInfoX509Data(new X509Certificate(cert), X509IncludeOption.EndCertOnly);
@@ -124,6 +126,7 @@ public void Constructor_X509CertificateNull_X509IncludeOption()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Constructor_X509Certificate_X509IncludeOptionBad()
         {
             KeyInfoX509Data data = new KeyInfoX509Data(new X509Certificate(cert), (X509IncludeOption)int.MinValue);
@@ -217,6 +220,7 @@ public void AddSubjectName_Null()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Complex()
         {
             KeyInfoX509Data data1 = new KeyInfoX509Data(cert);
@@ -279,6 +283,7 @@ public void CRL()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void ImportX509Data()
         {
             string simple = "<X509Data xmlns=\"http://www.w3.org/2000/09/xmldsig#\"><X509Certificate>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";
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/Samples/SigningVerifyingX509Cert.cs b/src/libraries/System.Security.Cryptography.Xml/tests/Samples/SigningVerifyingX509Cert.cs
index c7ea502fbd5c86..ca68ee3e791447 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/Samples/SigningVerifyingX509Cert.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/Samples/SigningVerifyingX509Cert.cs
@@ -59,6 +59,7 @@ private static bool VerifyXml(string signedXmlText, X509Certificate2 certificate
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SignedXmlHasCertificateVerifiableSignature()
         {
             using (X509Certificate2 x509cert = TestHelpers.GetSampleX509Certificate())
diff --git a/src/libraries/System.Security.Cryptography.Xml/tests/SignedXmlTest.cs b/src/libraries/System.Security.Cryptography.Xml/tests/SignedXmlTest.cs
index 600b4747b38d65..54caa519ac66bf 100644
--- a/src/libraries/System.Security.Cryptography.Xml/tests/SignedXmlTest.cs
+++ b/src/libraries/System.Security.Cryptography.Xml/tests/SignedXmlTest.cs
@@ -288,6 +288,7 @@ public void AsymmetricRSAMixedCaseAttributesVerifyWindows()
 
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/20575", TestPlatforms.OSX)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void AsymmetricDSASignature()
         {
             SignedXml signedXml = MSDNSample();
@@ -387,6 +388,7 @@ public void AsymmetricRSAVerify()
         // Using empty constructor
         // The two other constructors don't seems to apply in verifying signatures
         [Fact]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public void AsymmetricDSAVerify()
         {
             string value = "<Signature xmlns=\"http://www.w3.org/2000/09/xmldsig#\"><SignedInfo><CanonicalizationMethod Algorithm=\"http://www.w3.org/TR/2001/REC-xml-c14n-20010315\" /><SignatureMethod Algorithm=\"http://www.w3.org/2000/09/xmldsig#dsa-sha1\" /><Reference URI=\"#MyObjectId\"><DigestMethod Algorithm=\"http://www.w3.org/2000/09/xmldsig#sha1\" /><DigestValue>/Vvq6sXEVbtZC8GwNtLQnGOy/VI=</DigestValue></Reference></SignedInfo><SignatureValue>BYz/qRGjGsN1yMFPxWa3awUZm1y4I/IxOQroMxkOteRGgk1HIwhRYw==</SignatureValue><KeyInfo><KeyValue xmlns=\"http://www.w3.org/2000/09/xmldsig#\"><DSAKeyValue><P>iglVaZ+LsSL8Y0aDXmFMBwva3xHqIypr3l/LtqBH9ziV2Sh1M4JVasAiKqytWIWt/s/Uk8Ckf2tO2Ww1vsNi1NL+Kg9T7FE52sn380/rF0miwGkZeidzm74OWhykb3J+wCTXaIwOzAWI1yN7FoeoN7wzF12jjlSXAXeqPMlViqk=</P><Q>u4sowiJMHilNRojtdmIuQY2YnB8=</Q><G>SdnN7d+wn1n+HH4Hr8MIryIRYgcXdbZ5TH7jAnuWc1koqRc1AZfcYAZ6RDf+orx6Lzn055FTFiN+1NHQfGUtXJCWW0zz0FVV1NJux7WRj8vGTldjJ5ef0oCenkpwDjcIxWsZgVobve4GPoyN1sAc1scnkJB59oupibklmF4y72A=</G><Y>XejzS8Z51yfl0zbYnxSYYbHqreSLjNCoGPB/KjM1TOyV5sMjz0StKtGrFWryTWc7EgvFY7kUth4e04VKf9HbK8z/FifHTXj8+Tszbjzw8GfInnBwLN+vJgbpnjtypmiI5Bm2nLiRbfkdAHP+OrKtr/EauM9GQfYuaxm3/Vj8B84=</Y><J>vGwGg9wqwwWP9xsoPoXu6kHArJtadiNKe9azBiUx5Ob883gd5wlKfEcGuKkBmBySGbgwxyOsIBovd9Kk48hF01ymfQzAAuHR0EdJECSsTsTTKVTLQNBU32O+PRbLYpv4E8kt6rNL83JLJCBY</J><Seed>sqzn8J6fd2gtEyq6YOqiUSHgPE8=</Seed><PgenCounter>sQ==</PgenCounter></DSAKeyValue></KeyValue></KeyInfo><Object Id=\"MyObjectId\"><MyElement xmlns=\"samples\">This is some text</MyElement></Object></Signature>";
@@ -639,6 +641,7 @@ public void GetIdElement_Null()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DigestValue_CRLF()
         {
             XmlDocument doc = CreateSomeXml("\r\n");
@@ -698,6 +701,7 @@ public void DigestValue_CRLF()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void DigestValue_LF()
         {
             XmlDocument doc = CreateSomeXml("\n");
@@ -757,6 +761,7 @@ public void DigestValue_LF()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SignedXML_CRLF_Invalid()
         {
             X509Certificate2 cert = new X509Certificate2(_pkcs12, "mono");
@@ -820,6 +825,7 @@ public void SignedXML_CRLF_Invalid()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SignedXML_CRLF_Valid()
         {
             X509Certificate2 cert = new X509Certificate2(_pkcs12, "mono");
@@ -877,6 +883,7 @@ public void SignedXML_CRLF_Valid()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void SignedXML_LF_Valid()
         {
             X509Certificate2 cert = new X509Certificate2(_pkcs12, "mono");
@@ -934,6 +941,7 @@ public void SignedXML_LF_Valid()
         }
 
         [Fact] // part of bug #79454
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51370", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void MultipleX509Certificates()
         {
             XmlDocument doc = null;
diff --git a/src/libraries/System.Text.Encoding/tests/Encoding/Encoding.cs b/src/libraries/System.Text.Encoding/tests/Encoding/Encoding.cs
index 059985fb69fa22..f4860b20cc314f 100644
--- a/src/libraries/System.Text.Encoding/tests/Encoding/Encoding.cs
+++ b/src/libraries/System.Text.Encoding/tests/Encoding/Encoding.cs
@@ -68,6 +68,7 @@ public static void GetEncodingsTest()
         [Theory]
         [MemberData(nameof(Encoding_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void VerifyCodePageAttributes(int codepage, string name, string bodyName, string headerName, bool isBrowserDisplay,
                                             bool isBrowserSave, bool isMailNewsDisplay, bool isMailNewsSave, int windowsCodePage)
         {
@@ -86,6 +87,7 @@ public static void VerifyCodePageAttributes(int codepage, string name, string bo
         [Theory]
         [MemberData(nameof(Normalization_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void NormalizationTest(int codepage, bool normalized, bool normalizedC, bool normalizedD, bool normalizedKC, bool normalizedKD)
         {
             Encoding encoding = Encoding.GetEncoding(codepage);
diff --git a/src/libraries/System.Text.Encoding/tests/Encoding/EncodingGetEncodingTests.cs b/src/libraries/System.Text.Encoding/tests/Encoding/EncodingGetEncodingTests.cs
index 2f19a82d50d2f3..608019a68146bb 100644
--- a/src/libraries/System.Text.Encoding/tests/Encoding/EncodingGetEncodingTests.cs
+++ b/src/libraries/System.Text.Encoding/tests/Encoding/EncodingGetEncodingTests.cs
@@ -91,6 +91,7 @@ public CodePageMapping(string name, int codepage)
         [ActiveIssue("https://github.com/dotnet/runtime/issues/38433", TestPlatforms.Browser)] // wasm doesn't honor runtimeconfig.json
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void TestEncodingNameAndCopdepageNumber()
         {
             foreach (var map in s_mapping)
@@ -103,6 +104,7 @@ public void TestEncodingNameAndCopdepageNumber()
         [ActiveIssue("https://github.com/dotnet/runtime/issues/38433", TestPlatforms.Browser)] // wasm doesn't honor runtimeconfig.json
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetEncoding_EncodingName()
         {
             using (new ThreadCultureChange(CultureInfo.InvariantCulture))
@@ -124,6 +126,7 @@ public void GetEncoding_EncodingName()
         [ActiveIssue("https://github.com/dotnet/runtime/issues/38433", TestPlatforms.Browser)] // wasm doesn't honor runtimeconfig.json
         [Fact]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void GetEncoding_WebName()
         {
             foreach (var mapping in s_codePageToWebNameMappings)
diff --git a/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingEncode.cs b/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingEncode.cs
index 7799f403d51653..c4a549786a30fa 100644
--- a/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingEncode.cs
+++ b/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingEncode.cs
@@ -62,6 +62,7 @@ public static IEnumerable<object[]> Encode_Basic_TestData()
         [Theory]
         [MemberData(nameof(Encode_Basic_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Encode_Basic(string source, int index, int count, byte[] expected)
         {
             Encode_Advanced(true, source, index, count, expected);
diff --git a/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingTests.cs b/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingTests.cs
index 84b5bbc71f7eba..0cfe89e4411d7a 100644
--- a/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingTests.cs
+++ b/src/libraries/System.Text.Encoding/tests/UTF7Encoding/UTF7EncodingTests.cs
@@ -55,6 +55,7 @@ public static IEnumerable<object[]> Encodings_TestData()
         [Theory]
         [MemberData(nameof(Encodings_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void WebName(UTF7Encoding encoding)
         {
             Assert.Equal("utf-7", encoding.WebName);
@@ -63,6 +64,7 @@ public void WebName(UTF7Encoding encoding)
         [Theory]
         [MemberData(nameof(Encodings_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void CodePage(UTF7Encoding encoding)
         {
             Assert.Equal(65000, encoding.CodePage);
@@ -71,6 +73,7 @@ public void CodePage(UTF7Encoding encoding)
         [Theory]
         [MemberData(nameof(Encodings_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void EncodingName(UTF7Encoding encoding)
         {
             Assert.NotEmpty(encoding.EncodingName); // Unicode (UTF-7) in en-US
@@ -79,6 +82,7 @@ public void EncodingName(UTF7Encoding encoding)
         [Theory]
         [MemberData(nameof(Encodings_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void IsSingleByte(UTF7Encoding encoding)
         {
             Assert.False(encoding.IsSingleByte);
@@ -87,6 +91,7 @@ public void IsSingleByte(UTF7Encoding encoding)
         [Theory]
         [MemberData(nameof(Encodings_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Clone(UTF7Encoding encoding)
         {
             UTF7Encoding clone = (UTF7Encoding)encoding.Clone();
@@ -121,6 +126,7 @@ public static IEnumerable<object[]> Equals_TestData()
         [Theory]
         [MemberData(nameof(Equals_TestData))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50573", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51394", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void EqualsTest(UTF7Encoding encoding, object value, bool expected)
         {
             Assert.Equal(expected, encoding.Equals(value));
diff --git a/src/libraries/System.Text.RegularExpressions/tests/Regex.Groups.Tests.cs b/src/libraries/System.Text.RegularExpressions/tests/Regex.Groups.Tests.cs
index 0b74edd62269b3..a413c06b3aae93 100644
--- a/src/libraries/System.Text.RegularExpressions/tests/Regex.Groups.Tests.cs
+++ b/src/libraries/System.Text.RegularExpressions/tests/Regex.Groups.Tests.cs
@@ -871,6 +871,7 @@ public static IEnumerable<object[]> Groups_CustomCulture_TestData_AzeriLatin()
         [MemberData(nameof(Groups_CustomCulture_TestData_Turkish))]
         [MemberData(nameof(Groups_CustomCulture_TestData_AzeriLatin))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/36848", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/36900", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void Groups(string cultureName, string pattern, string input, RegexOptions options, string[] expectedGroups)
         {
             if (cultureName is null)
diff --git a/src/libraries/System.Threading.Tasks/tests/MethodCoverage.cs b/src/libraries/System.Threading.Tasks/tests/MethodCoverage.cs
index e696a38cf924e1..c005e2623511d6 100644
--- a/src/libraries/System.Threading.Tasks/tests/MethodCoverage.cs
+++ b/src/libraries/System.Threading.Tasks/tests/MethodCoverage.cs
@@ -322,6 +322,7 @@ public static void TaskConfigurableAwaiter()
         /// FromAsync testing: Not supported in .NET Native
         /// </summary>
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/52614", TestPlatforms.iOS | TestPlatforms.tvOS)]
         public static void FromAsync()
         {
             Task emptyTask = new Task(() => { });
diff --git a/src/libraries/System.Threading.Thread/tests/ThreadTests.cs b/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
index 260399635e82c9..e89935d78777dd 100644
--- a/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
+++ b/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
@@ -171,6 +171,7 @@ public static IEnumerable<object[]> ApartmentStateTest_MemberData()
         [InlineData("DefaultApartmentStateMain.exe", "SetApartmentStateTest")]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49568", typeof(PlatformDetection), nameof(PlatformDetection.IsMacOsAppleSilicon))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/50577", TestPlatforms.Android)]
+        [SkipOnPlatform(TestPlatforms.iOS | TestPlatforms.tvOS, "Not supported on iOS or tvOS.")]
         public static void ApartmentState_AttributePresent(string appName, string testName)
         {
             var psi = new ProcessStartInfo();
diff --git a/src/libraries/System.Threading/tests/AutoResetEventTests.cs b/src/libraries/System.Threading/tests/AutoResetEventTests.cs
index dba9b4b46df64e..f7418857507e93 100644
--- a/src/libraries/System.Threading/tests/AutoResetEventTests.cs
+++ b/src/libraries/System.Threading/tests/AutoResetEventTests.cs
@@ -87,6 +87,7 @@ public void WaitHandleWaitAny()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void PingPong()
         {
             using (AutoResetEvent are1 = new AutoResetEvent(true), are2 = new AutoResetEvent(false))
diff --git a/src/libraries/System.Threading/tests/ExecutionContextTests.cs b/src/libraries/System.Threading/tests/ExecutionContextTests.cs
index d813813bbc5535..7e8eb3d6d4cea7 100644
--- a/src/libraries/System.Threading/tests/ExecutionContextTests.cs
+++ b/src/libraries/System.Threading/tests/ExecutionContextTests.cs
@@ -63,6 +63,7 @@ public static void DisposeTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void FlowTest()
         {
             ThreadTestHelpers.RunTestInBackgroundThread(() =>
@@ -170,6 +171,7 @@ public static void FlowTest()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void CaptureThenSuppressThenRunFlowTest()
         {
             ThreadTestHelpers.RunTestInBackgroundThread(() =>
diff --git a/src/libraries/System.Threading/tests/ManualResetEventTests.cs b/src/libraries/System.Threading/tests/ManualResetEventTests.cs
index 5d170f089c0f0b..c3d57ae881dcf8 100644
--- a/src/libraries/System.Threading/tests/ManualResetEventTests.cs
+++ b/src/libraries/System.Threading/tests/ManualResetEventTests.cs
@@ -72,6 +72,7 @@ public void WaitHandleWaitAny()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void PingPong()
         {
             using (ManualResetEvent mre1 = new ManualResetEvent(true), mre2 = new ManualResetEvent(false))
diff --git a/src/libraries/System.Threading/tests/ReaderWriterLockTests.cs b/src/libraries/System.Threading/tests/ReaderWriterLockTests.cs
index d7c08c6711865b..8eb7b253911c16 100644
--- a/src/libraries/System.Threading/tests/ReaderWriterLockTests.cs
+++ b/src/libraries/System.Threading/tests/ReaderWriterLockTests.cs
@@ -123,6 +123,7 @@ public static void InvalidLockCookieTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void BasicLockTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -512,6 +513,7 @@ public static void WaitingReadersTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void WaitingWritersTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -544,6 +546,7 @@ public static void WaitingWritersTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ReadersWaitingOnWaitingWriterTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -595,6 +598,7 @@ public static void ReadersWaitingOnWaitingWriterTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void ReadersWaitingOnWaitingUpgraderTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -649,6 +653,7 @@ public static void ReadersWaitingOnWaitingUpgraderTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void WaitingUpgradersTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -695,6 +700,7 @@ public static void WaitingUpgradersTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AtomicRecursiveReaderTest()
         {
             var trwl = new TestReaderWriterLock();
@@ -722,6 +728,7 @@ public static void AtomicRecursiveReaderTest()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public static void AtomicDowngradeTest()
         {
             var trwl = new TestReaderWriterLock();
diff --git a/src/libraries/System.Threading/tests/SemaphoreTests.cs b/src/libraries/System.Threading/tests/SemaphoreTests.cs
index 35d52e599dbfc8..9859795025edbe 100644
--- a/src/libraries/System.Threading/tests/SemaphoreTests.cs
+++ b/src/libraries/System.Threading/tests/SemaphoreTests.cs
@@ -140,6 +140,7 @@ public void Release()
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/49890", TestPlatforms.Android)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/51400", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
         public void AnonymousProducerConsumer()
         {
             using (Semaphore s = new Semaphore(0, int.MaxValue))
diff --git a/src/libraries/tests.proj b/src/libraries/tests.proj
index 3b69f941797b0a..21c306e3a9e999 100644
--- a/src/libraries/tests.proj
+++ b/src/libraries/tests.proj
@@ -135,114 +135,67 @@
   </ItemGroup>
 
   <ItemGroup Condition="('$(TargetOS)' == 'iOS' or '$(TargetOS)' == 'iOSSimulator' or '$(TargetOS)' == 'tvOS' or '$(TargetOS)' == 'tvOSSimulator' or '$(TargetOS)' == 'MacCatalyst') and '$(RunDisablediOSTests)' != 'true'">
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.Extensions.FileProviders.Composite\tests\Microsoft.Extensions.FileProviders.Composite.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.Extensions.HostFactoryResolver\tests\Microsoft.Extensions.HostFactoryResolver.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.Extensions.Hosting\tests\UnitTests\Microsoft.Extensions.Hosting.Unit.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.Extensions.Logging.Console\tests\Microsoft.Extensions.Logging.Console.Tests\Microsoft.Extensions.Logging.Console.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.VisualBasic.Core\tests\Microsoft.VisualBasic.Core.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Collections.Immutable\tests\System.Collections.Immutable.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Collections.Specialized\tests\System.Collections.Specialized.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.ComponentModel.Primitives\tests\System.ComponentModel.Primitives.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.ComponentModel.TypeConverter\tests\System.ComponentModel.TypeConverter.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Console\tests\System.Console.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Data.Common\tests\System.Data.Common.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.Debug\tests\System.Diagnostics.Debug.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.DiagnosticSource\tests\TestWithConfigSwitches\System.Diagnostics.DiagnosticSource.Switches.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.Process\tests\System.Diagnostics.Process.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.StackTrace\tests\System.Diagnostics.StackTrace.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.Tracing\tests\System.Diagnostics.Tracing.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Formats.Cbor\tests\System.Formats.Cbor.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Compression.Brotli\tests\System.IO.Compression.Brotli.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.FileSystem\tests\System.IO.FileSystem.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.FileSystem.Watcher\tests\System.IO.FileSystem.Watcher.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.IsolatedStorage\tests\System.IO.IsolatedStorage.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.MemoryMappedFiles\tests\System.IO.MemoryMappedFiles.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Pipes\tests\System.IO.Pipes.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Ports\tests\System.IO.Ports.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO\tests\System.IO.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Linq.Parallel\tests\System.Linq.Parallel.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Memory\tests\System.Memory.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Http.Json\tests\FunctionalTests\System.Net.Http.Json.Functional.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Http\tests\EnterpriseTests\System.Net.Http.Enterprise.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Mail\tests\Unit\System.Net.Mail.Unit.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.NameResolution\tests\FunctionalTests\System.Net.NameResolution.Functional.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.NameResolution\tests\UnitTests\System.Net.NameResolution.Unit.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.NetworkInformation\tests\FunctionalTests\System.Net.NetworkInformation.Functional.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Ping\tests\FunctionalTests\System.Net.Ping.Functional.Tests.csproj" />
-
-    <!-- https://github.com/dotnet/runtime/issues/49191 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Quic\tests\FunctionalTests\System.Net.Quic.Functional.Tests.csproj" />
+    <!-- PNSE -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Quic/tests/FunctionalTests/System.Net.Quic.Functional.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/51414 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.OpenSsl/tests/System.Security.Cryptography.OpenSsl.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/36897 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.X509Certificates/tests/System.Security.Cryptography.X509Certificates.Tests.csproj" />
 
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Requests\tests\System.Net.Requests.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Security\tests\FunctionalTests\System.Net.Security.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Sockets\tests\FunctionalTests\System.Net.Sockets.Tests.csproj" />
+    <!-- Failures -->
+    <!-- https://github.com/dotnet/runtime/issues/51335 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Pipes/tests/System.IO.Pipes.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/51330 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Pkcs/tests/System.Security.Cryptography.Pkcs.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/51370 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Xml/tests/System.Security.Cryptography.Xml.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/51338 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Private.Xml/tests/XmlSchema/XmlSchemaValidatorApi/System.Xml.XmlSchema.XmlSchemaValidatorApi.Tests.csproj" />
+
+    <!-- Crashes or hangs, did not produce testResults.xml -->
+    <!-- https://github.com/dotnet/runtime/issues/52117 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Requests/tests/System.Net.Requests.Tests.csproj" />
+    <!-- https://github.com/dotnet/runtime/issues/52120 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Security/tests/FunctionalTests/System.Net.Security.Tests.csproj" />
+
+    <!-- Crashes on CI but passes locally https://github.com/dotnet/runtime/issues/52615 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Compression/tests/System.IO.Compression.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Csp/tests/System.Security.Cryptography.Csp.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Tasks.Dataflow/tests/System.Threading.Tasks.Dataflow.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Tasks/tests/System.Threading.Tasks.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Private.Xml/tests/XmlResolver/System.Xml.XmlResolver.Tests/System.Xml.XmlResolver.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Packaging/tests/System.IO.Packaging.Tests.csproj" />
 
-    <!-- https://github.com/dotnet/runtime/issues/49192-->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.WebClient\tests\System.Net.WebClient.Tests.csproj" />
+    <!-- System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Algorithms/tests/System.Security.Cryptography.Algorithms.Tests.csproj" />
 
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.WebSockets\tests\System.Net.WebSockets.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.WebSockets.Client\tests\System.Net.WebSockets.Client.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Numerics.Tensors\tests\System.Numerics.Tensors.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Reflection.Context\tests\System.Reflection.Context.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Reflection\tests\System.Reflection.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Resources.ResourceManager\tests\System.Resources.ResourceManager.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime.Extensions\tests\System.Runtime.Extensions.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime.InteropServices.JavaScript\tests\System.Runtime.InteropServices.JavaScript.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime.InteropServices.RuntimeInformation\tests\System.Runtime.InteropServices.RuntimeInformation.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime\tests\System.Runtime.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Algorithms\tests\System.Security.Cryptography.Algorithms.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Csp\tests\System.Security.Cryptography.Csp.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Encoding\tests\System.Security.Cryptography.Encoding.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.OpenSsl\tests\System.Security.Cryptography.OpenSsl.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Pkcs\tests\System.Security.Cryptography.Pkcs.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.X509Certificates\tests\System.Security.Cryptography.X509Certificates.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Security.Cryptography.Xml\tests\System.Security.Cryptography.Xml.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.ServiceModel.Syndication\tests\System.ServiceModel.Syndication.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.Encoding\tests\System.Text.Encoding.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.RegularExpressions\tests\System.Text.RegularExpressions.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Overlapped\tests\System.Threading.Overlapped.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Tasks.Extensions\tests\System.Threading.Tasks.Extensions.Tests.csproj" />
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-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading\tests\System.Threading.Tests.csproj" />
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-    <!-- Skipping - Most likely from https://github.com/dotnet/runtime/issues/50245 -->
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-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Timer\tests\System.Threading.Timer.Tests.csproj" />
+  <ItemGroup Condition="('$(TargetOS)' == 'tvOS' or '$(TargetOS)' == 'tvOSSimulator') and '$(RunDisablediOSTests)' != 'true'">
+    <!-- https://github.com/dotnet/runtime/issues/50589 -->
+    <ProjectExclusions Include="$(RepoRoot)\src\tests\FunctionalTests\tvOS\Simulator\AOT\tvOS.Simulator.Aot.Test.csproj" />
 
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-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Private.Xml.Linq\tests\xNodeReader\System.Xml.Linq.xNodeReader.Tests.csproj" />
+    <!-- Crashes on CI but passes locally https://github.com/dotnet/runtime/issues/52615 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.Compression.ZipFile/tests/System.IO.Compression.ZipFile.Tests.csproj" />
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     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Tasks.Dataflow\tests\System.Threading.Tasks.Dataflow.Tests.csproj" />
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-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Private.Xml/tests/XmlDocument/System.Xml.XmlDocument.Tests.csproj" />
+    <!-- PNSE -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Diagnostics.Process/tests/System.Diagnostics.Process.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime.Extensions/tests/System.Runtime.Extensions.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.NetworkInformation/tests/FunctionalTests/System.Net.NetworkInformation.Functional.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.Extensions.Hosting/tests/UnitTests/Microsoft.Extensions.Hosting.Unit.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)Microsoft.VisualBasic.Core/tests/Microsoft.VisualBasic.Core.Tests.csproj" />
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+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Console/tests/System.Console.Tests.csproj" />
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