diff --git a/tests/FSharp.Compiler.Service.Tests/AssemblyInfo.fs b/tests/FSharp.Compiler.Service.Tests/AssemblyInfo.fs
deleted file mode 100644
index 3433f928ba4..00000000000
--- a/tests/FSharp.Compiler.Service.Tests/AssemblyInfo.fs
+++ /dev/null
@@ -1,7 +0,0 @@
-module FSharp.Compiler.Service.Tests.AssemblyInfo
-
-open Xunit
-
-[<assembly: CollectionBehavior(DisableTestParallelization = true)>]
-
-do()
diff --git a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
index 831143ba698..59094ee50da 100644
--- a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
+++ b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
@@ -19,7 +19,6 @@
     <Content Include="expected-help-output.bsl">
       <CopyToOutputDirectory>Never</CopyToOutputDirectory>
     </Content>
-    <Compile Include="AssemblyInfo.fs" />
     <Compile Include="SurfaceArea.fs" Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'" />
     <Compile Include="..\service\FsUnit.fs">
       <Link>FsUnit.fs</Link>
diff --git a/tests/FSharp.Compiler.Service.Tests/MultiProjectAnalysisTests.fs b/tests/FSharp.Compiler.Service.Tests/MultiProjectAnalysisTests.fs
index 22c17f48871..ef753a6bc3e 100644
--- a/tests/FSharp.Compiler.Service.Tests/MultiProjectAnalysisTests.fs
+++ b/tests/FSharp.Compiler.Service.Tests/MultiProjectAnalysisTests.fs
@@ -448,7 +448,8 @@ let z = Project1.x
 [<InlineData(false)>]
 let ``Test multi project symbols should pick up changes in dependent projects`` useTransparentCompiler =
 
-    let checker = if useTransparentCompiler then transparentCompilerChecker else checker
+    // A private checker because we subscribe to FileChecked.
+    let checker = FSharpChecker.Create(useTransparentCompiler = useTransparentCompiler)
 
     //  register to count the file checks
     let count = ref 0
diff --git a/tests/FSharp.Compiler.Service.Tests/ProjectAnalysisTests.fs b/tests/FSharp.Compiler.Service.Tests/ProjectAnalysisTests.fs
index b52435e54a5..8bfc0a67e9a 100644
--- a/tests/FSharp.Compiler.Service.Tests/ProjectAnalysisTests.fs
+++ b/tests/FSharp.Compiler.Service.Tests/ProjectAnalysisTests.fs
@@ -1,6 +1,7 @@
 module FSharp.Compiler.Service.Tests.ProjectAnalysisTests
 
 #nowarn "57" // Experimental stuff
+open FSharp.Compiler.CodeAnalysis
 
 let runningOnMono = try System.Type.GetType("Mono.Runtime") <> null with e ->  false
 
@@ -19,8 +20,6 @@ open FSharp.Compiler.Symbols
 open FSharp.Compiler.Symbols.FSharpExprPatterns
 open TestFramework
 
-// Exculde because of some GC tests
-[<Collection(nameof DoNotRunInParallel)>]
 module internal Project1 =
 
     let fileName1 = Path.ChangeExtension(getTemporaryFileName (), ".fs")
@@ -110,6 +109,9 @@ let ``Test project1 whole project errors`` () =
 [<Fact>]
 let ``Test project1 and make sure TcImports gets cleaned up`` () =
 
+    // A private checker for this test.
+    let checker = FSharpChecker.Create(useTransparentCompiler = FSharp.Test.TestContext.UseTransparentCompiler)    
+
     let test () =
         let _, checkFileAnswer = checker.ParseAndCheckFileInProject(Project1.fileName1, 0, Project1.fileSource1, Project1.options) |> Async.RunImmediate
         match checkFileAnswer with
diff --git a/tests/FSharp.Test.Utilities/XunitHelpers.fs b/tests/FSharp.Test.Utilities/XunitHelpers.fs
index 07c3dd3df5c..72d6c40aa8a 100644
--- a/tests/FSharp.Test.Utilities/XunitHelpers.fs
+++ b/tests/FSharp.Test.Utilities/XunitHelpers.fs
@@ -14,14 +14,14 @@ open Xunit.Abstractions
 type RunInSequenceAttribute() = inherit Attribute()
 
 #if !XUNIT_EXTRAS
-/// Installs console support for parallel test runs and conditionally enables optional xUnit customizations.
+/// Installs console support for parallel test runs.
 type FSharpXunitFramework(sink: IMessageSink) =
     inherit XunitTestFramework(sink)
     do
         // Because xUnit v2 lacks assembly fixture, the next best place to ensure things get called
         // right at the start of the test run is here in the constructor.
         // This gets executed once per test assembly.
-        MessageSink.sinkWriter |> ignore
+        log "FSharpXunitFramework installing TestConsole redirection"
         TestConsole.install()
 
 #else
@@ -129,7 +129,7 @@ type FSharpXunitFramework(sink: IMessageSink) =
         // Because xUnit v2 lacks assembly fixture, the next best place to ensure things get called
         // right at the start of the test run is here in the constructor.
         // This gets executed once per test assembly.
-        MessageSink.sinkWriter |> ignore
+        log "FSharpXunitFramework with XUNIT_EXTRAS installing TestConsole redirection"
         TestConsole.install() 
 
     override this.CreateDiscoverer (assemblyInfo) =