diff --git a/MSBuild.sln b/MSBuild.sln
index 105c979813e..966817afd12 100644
--- a/MSBuild.sln
+++ b/MSBuild.sln
@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.27004.2009
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30320.27
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{4900B3B8-4310-4D5B-B1F7-2FDF9199765F}"
 	ProjectSection(SolutionItems) = preProject
@@ -65,6 +65,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MSBuild.Engine.Corext", "sr
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MSBuild.Bootstrap", "src\MSBuild.Bootstrap\MSBuild.Bootstrap.csproj", "{CEAEE4FE-9298-443B-AFC5-0F72472484B6}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Build.UnGAC", "src\Package\Microsoft.Build.UnGAC\Microsoft.Build.UnGAC.csproj", "{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -834,6 +836,36 @@ Global
 		{CEAEE4FE-9298-443B-AFC5-0F72472484B6}.Release-MONO|x64.Build.0 = Release-MONO|x64
 		{CEAEE4FE-9298-443B-AFC5-0F72472484B6}.Release-MONO|x86.ActiveCfg = Release-MONO|Any CPU
 		{CEAEE4FE-9298-443B-AFC5-0F72472484B6}.Release-MONO|x86.Build.0 = Release-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|x64.ActiveCfg = Debug|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|x64.Build.0 = Debug|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug|x86.Build.0 = Debug|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|Any CPU.ActiveCfg = Debug-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|Any CPU.Build.0 = Debug-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|x64.ActiveCfg = Debug-MONO|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|x64.Build.0 = Debug-MONO|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|x86.ActiveCfg = Debug-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Debug-MONO|x86.Build.0 = Debug-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|Any CPU.ActiveCfg = MachineIndependent|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|Any CPU.Build.0 = MachineIndependent|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|x64.ActiveCfg = MachineIndependent|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|x64.Build.0 = MachineIndependent|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|x86.ActiveCfg = MachineIndependent|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.MachineIndependent|x86.Build.0 = MachineIndependent|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|x64.ActiveCfg = Release|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|x64.Build.0 = Release|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|x86.ActiveCfg = Release|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release|x86.Build.0 = Release|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|Any CPU.ActiveCfg = Release-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|Any CPU.Build.0 = Release-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|x64.ActiveCfg = Release-MONO|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|x64.Build.0 = Release-MONO|x64
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|x86.ActiveCfg = Release-MONO|Any CPU
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F}.Release-MONO|x86.Build.0 = Release-MONO|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -850,6 +882,7 @@ Global
 		{16DBDF17-3E0E-4140-989A-B42638126A40} = {9BAD9352-DEFB-45E5-B8A4-4816B9B22A33}
 		{EDBFE32E-F264-4F01-97C3-B58F8B9165C9} = {9BAD9352-DEFB-45E5-B8A4-4816B9B22A33}
 		{3D67E4FF-6EC6-4FE7-82F1-0DACE1E399A7} = {9BAD9352-DEFB-45E5-B8A4-4816B9B22A33}
+		{B60173F0-F9F0-4688-9DF8-9ADDD57BD45F} = {9BAD9352-DEFB-45E5-B8A4-4816B9B22A33}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {F948D667-14E3-4F98-BA50-3F3C948BF4C2}
diff --git a/eng/Signing.props b/eng/Signing.props
index 13912cb79a5..b07f715e5ab 100644
--- a/eng/Signing.props
+++ b/eng/Signing.props
@@ -2,7 +2,7 @@
     <ItemGroup>
 		<FileSignInfo Include="Nerdbank.Streams.dll" CertificateName="3PartySHA2" /> 
 		<FileSignInfo Include="MessagePack.dll" CertificateName="3PartySHA2" /> 
-		<FileSignInfo Include="MessagePack.Annotations.dll" CertificateName="3PartySHA2" /> 
-		<ItemsToSign Include="$(VisualStudioSetupOutputPath)DevDivPackages\*.nupkg" />
+		<FileSignInfo Include="MessagePack.Annotations.dll" CertificateName="3PartySHA2" />
+		<ItemsToSign Include="$(VisualStudioSetupInsertionPath)Microsoft.Build.UnGAC.exe" />
 	</ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/src/Package/MSBuild.VSSetup/files.swr b/src/Package/MSBuild.VSSetup/files.swr
index d813b8deb3d..8449a0b7149 100644
--- a/src/Package/MSBuild.VSSetup/files.swr
+++ b/src/Package/MSBuild.VSSetup/files.swr
@@ -6,6 +6,7 @@ package name=Microsoft.Build
         vs.package.language=neutral
 
 vs.dependencies
+  vs.dependency id=Microsoft.Build.UnGAC
   vs.dependency id=Microsoft.VisualStudio.PackageGroup.NuGet
                 version=[15.0,17.0)
 
diff --git a/src/Package/Microsoft.Build.UnGAC/Microsoft.Build.UnGAC.csproj b/src/Package/Microsoft.Build.UnGAC/Microsoft.Build.UnGAC.csproj
new file mode 100644
index 00000000000..6282c3a2134
--- /dev/null
+++ b/src/Package/Microsoft.Build.UnGAC/Microsoft.Build.UnGAC.csproj
@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <!-- Setup runs on net45 and may not have installed newer yet. -->
+    <TargetFramework>net45</TargetFramework>
+    <!-- Set as an exe because this project publishes its own output. -->
+    <OutputType>Exe</OutputType>
+    <!-- Forcing the 'vsix' output to be json output. Workaround for https://github.com/dotnet/arcade/issues/6120 -->
+    <TargetVsixContainerName>Microsoft.Build.UnGAC.exe</TargetVsixContainerName>
+    <!-- VS Insertion -->
+    <VisualStudioInsertionComponent>Microsoft.Build.UnGAC</VisualStudioInsertionComponent>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <_SwixArgs Include="PackageType=manifest"/>
+    <!-- If we don't set TargetExt to .json, arcade defaults to generating a .vsix -->
+    <_SwixArgs Include="TargetExt=.json"/>
+  </ItemGroup>
+
+  <!-- SwrProperty is an arcade concept. -->
+  <ItemGroup>
+    <!-- BinDir is set via SwrProperty to be passed to the swr compiler. OutDir is the path to the bin folder. See exe.swr to see how this is used. -->
+    <SwrProperty Include="BinDir=$(OutDir)" />
+    <!-- Version must constantly update in order for our exe package to run on install and update. -->
+    <SwrProperty Include="Version=$(VsixVersion)" />
+
+    <!-- our swr file must be picked up, this is how we set that. -->
+    <SwrFile Include="exe.swr" Condition=" '$(MSBuildRuntimeType)' == 'Full' " />
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/src/Package/Microsoft.Build.UnGAC/NativeMethods.cs b/src/Package/Microsoft.Build.UnGAC/NativeMethods.cs
new file mode 100644
index 00000000000..f468942cf12
--- /dev/null
+++ b/src/Package/Microsoft.Build.UnGAC/NativeMethods.cs
@@ -0,0 +1,22 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Microsoft.Build.UnGAC
+{
+    // See: https://docs.microsoft.com/en-us/dotnet/framework/unmanaged-api/fusion/iassemblycache-interface
+    [ComImport, Guid("E707DCDE-D1CD-11D2-BAB9-00C04F8ECEAE"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    internal interface IAssemblyCache
+    {
+        [PreserveSig]
+        uint UninstallAssembly(uint dwFlags, [MarshalAs(UnmanagedType.LPWStr)] string pszAssemblyName, IntPtr pRefData, ref ulong pulDisposition);
+    }
+
+    public static class NativeMethods
+    {
+        [DllImport("fusion.dll")]
+        internal static extern uint CreateAssemblyCache(out IAssemblyCache ppAsmCache, int dwReserved);
+    }
+}
diff --git a/src/Package/Microsoft.Build.UnGAC/Program.cs b/src/Package/Microsoft.Build.UnGAC/Program.cs
new file mode 100644
index 00000000000..c5b5caa710d
--- /dev/null
+++ b/src/Package/Microsoft.Build.UnGAC/Program.cs
@@ -0,0 +1,53 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace Microsoft.Build.UnGAC
+{
+    /// <summary>
+    /// Original Issue: https://github.com/dotnet/msbuild/issues/5183
+    /// This tool was created to help prevent customers from putting MSBuild assemblies in the Global Assembly Cache.
+    /// It runs at VS install-time as well as repair-time.
+    /// It is intended to run as best effort. Meaning that if it fails, we avoid throwing and instead log it.
+    /// </summary>
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            try
+            {
+                string[] assembliesToUnGAC =
+                {
+                    "Microsoft.Build, Version=15.1.0.0",
+                    "Microsoft.Build.Engine, Version=15.1.0.0",
+                    "Microsoft.Build.Framework, Version=15.1.0.0",
+                    "Microsoft.Build.Tasks.Core, Version=15.1.0.0",
+                    "Microsoft.Build.Utilities.Core, Version=15.1.0.0",
+                    "Microsoft.Build.Conversion.Core, Version=15.1.0.0"
+                };
+
+                uint hresult = NativeMethods.CreateAssemblyCache(out IAssemblyCache assemblyCache, 0);
+
+                // Most significant bit is set, meaning there was an error in the Hresult.
+                if ((hresult >> 31) == 1)
+                {
+                    Console.WriteLine($"Could not successfully call CreateAssemblyCache. HResult: {hresult}");
+                    Console.WriteLine("Exiting without removing assemblies from the GAC...");
+                    return;
+                }
+
+                foreach (string assembly in assembliesToUnGAC)
+                {
+                    hresult = assemblyCache.UninstallAssembly(dwFlags: 0, pszAssemblyName: assembly, pRefData: IntPtr.Zero, pulDisposition: 0);
+
+                    Console.WriteLine($"Tried to remove {assembly} from the GAC. HResult: 0x{hresult:X8}");
+                }
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine($"Caught an exception! We don't want to throw because we want MSBuild to install.\n" + e.ToString());
+            }
+        }
+    }
+}
diff --git a/src/Package/Microsoft.Build.UnGAC/exe.swr b/src/Package/Microsoft.Build.UnGAC/exe.swr
new file mode 100644
index 00000000000..9a717021a50
--- /dev/null
+++ b/src/Package/Microsoft.Build.UnGAC/exe.swr
@@ -0,0 +1,19 @@
+use vs
+
+package name=Microsoft.Build.UnGAC
+        version=$(Version)
+        vs.package.type=exe
+        vs.package.chip=neutral
+        vs.package.language=neutral
+
+vs.installCommand fileName=[Payload]
+
+vs.repairCommand fileName=[Payload]
+
+vs.installSize
+  SystemDrive=0
+  TargetDrive=0
+  SharedDrive=0
+
+vs.payloads
+    vs.payload source=$(BinDir)Microsoft.Build.UnGAC.exe