diff --git a/src/libraries/System.Diagnostics.Process/tests/Interop.cs b/src/libraries/System.Diagnostics.Process/tests/Interop.cs
index e7388724a38999..449db3f9c3c985 100644
--- a/src/libraries/System.Diagnostics.Process/tests/Interop.cs
+++ b/src/libraries/System.Diagnostics.Process/tests/Interop.cs
@@ -75,7 +75,7 @@ public struct SID_AND_ATTRIBUTES
         [DllImport("netapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
         internal static extern uint NetUserAdd(string servername, uint level, ref USER_INFO_1 buf, out uint parm_err);
 
-        [DllImport("netapi32.dll")]
+        [DllImport("netapi32.dll", CharSet = CharSet.Unicode)]
         internal static extern uint NetUserDel(string servername, string username);
 
         [DllImport("advapi32.dll")]
@@ -94,7 +94,7 @@ internal static void NetUserAdd(string username, string password)
             uint parm_err;
             uint result = NetUserAdd(null, 1, ref userInfo, out parm_err);
 
-            if (result != 0) // NERR_Success
+            if (result != ExitCodes.NERR_Success)
             {
                 // most likely result == ERROR_ACCESS_DENIED
                 // due to running without elevated privileges
@@ -132,5 +132,11 @@ internal static bool ProcessTokenToSid(SafeProcessHandle token, out SecurityIden
                     Marshal.FreeHGlobal(tu);
             }
         }
+
+        internal static class ExitCodes
+        {
+            internal const uint NERR_Success = 0;
+            internal const uint NERR_UserNotFound = 2221;
+        }
     }
 }
diff --git a/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs b/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
index 38c626ec2a8190..1493c990dedc76 100644
--- a/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
+++ b/src/libraries/System.Diagnostics.Process/tests/ProcessStartInfoTests.cs
@@ -17,6 +17,7 @@
 using Microsoft.Win32;
 using Microsoft.Win32.SafeHandles;
 using Xunit;
+using System.Security.AccessControl;
 
 namespace System.Diagnostics.Tests
 {
@@ -24,6 +25,8 @@ public class ProcessStartInfoTests : ProcessTestBase
     {
         private const string ItemSeparator = "CAFF9451396B4EEF8A5155A15BDC2080"; // random string that shouldn't be in any env vars; used instead of newline to separate env var strings
 
+        private static bool IsNotWindowsNanoServerAndRemoteExecutorIsSupported => PlatformDetection.IsNotWindowsNanoServer && RemoteExecutor.IsSupported;
+
         [Fact]
         public void TestEnvironmentProperty()
         {
@@ -447,21 +450,18 @@ public void TestWorkingDirectoryPropertyInChildProcess()
             }, workingDirectory, new RemoteInvokeOptions { StartInfo = psi }).Dispose();
         }
 
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/18978")]
-                [ConditionalFact(typeof(RemoteExecutor), nameof(RemoteExecutor.IsSupported)), PlatformSpecific(TestPlatforms.Windows), OuterLoop] // Uses P/Invokes, Requires admin privileges
+        [ConditionalFact(nameof(IsNotWindowsNanoServerAndRemoteExecutorIsSupported))] // Nano has no "netapi32.dll"
+        [PlatformSpecific(TestPlatforms.Windows)]
+        [OuterLoop("Requires admin privileges")] 
         public void TestUserCredentialsPropertiesOnWindows()
         {
             // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Unit test dummy credentials.")]
-            string username = "test", password = "PassWord123!!";
-            try
-            {
-                Interop.NetUserAdd(username, password);
-            }
-            catch (Exception exc)
-            {
-                Console.Error.WriteLine("TestUserCredentialsPropertiesOnWindows: NetUserAdd failed: {0}", exc.Message);
-                return; // test is irrelevant if we can't add a user
-            }
+            const string username = "testForDotnetRuntime", password = "PassWord123!!";
+
+            uint removalResult = Interop.NetUserDel(null, username);
+            Assert.True(removalResult == Interop.ExitCodes.NERR_Success || removalResult == Interop.ExitCodes.NERR_UserNotFound);
+
+            Interop.NetUserAdd(username, password);
 
             bool hasStarted = false;
             SafeProcessHandle handle = null;
@@ -471,6 +471,9 @@ public void TestUserCredentialsPropertiesOnWindows()
             {
                 p = CreateProcessLong();
 
+                // ensure the new user can access the .exe (otherwise you get Access is denied exception)
+                SetAccessControl(username, p.StartInfo.FileName, AccessControlType.Allow);
+
                 p.StartInfo.LoadUserProfile = true;
                 p.StartInfo.UserName = username;
                 p.StartInfo.PasswordInClearText = password;
@@ -496,8 +499,9 @@ public void TestUserCredentialsPropertiesOnWindows()
             }
             finally
             {
-                IEnumerable<uint> collection = new uint[] { 0 /* NERR_Success */, 2221 /* NERR_UserNotFound */ };
-                Assert.Contains<uint>(Interop.NetUserDel(null, username), collection);
+                SetAccessControl(username, p.StartInfo.FileName, AccessControlType.Deny); // revoke the access
+
+                Assert.Equal(Interop.ExitCodes.NERR_Success, Interop.NetUserDel(null, username));
 
                 if (handle != null)
                     handle.Dispose();
@@ -511,6 +515,14 @@ public void TestUserCredentialsPropertiesOnWindows()
             }
         }
 
+        private static void SetAccessControl(string userName, string filePath, AccessControlType accessControlType)
+        {
+            FileInfo fileInfo = new FileInfo(filePath);
+            FileSecurity accessControl = fileInfo.GetAccessControl();
+            accessControl.AddAccessRule(new FileSystemAccessRule(userName, FileSystemRights.ReadAndExecute, accessControlType));
+            fileInfo.SetAccessControl(accessControl);
+        }
+
         private static List<string> GetNamesOfUserProfiles()
         {
             List<string> userNames = new List<string>();