diff --git a/.vsts-ci/windows.yml b/.vsts-ci/windows.yml
index dab9f6b295f..d2d94b98234 100644
--- a/.vsts-ci/windows.yml
+++ b/.vsts-ci/windows.yml
@@ -90,8 +90,8 @@ jobs:
 
   - powershell: |
       Import-Module .\tools\ci.psm1
-      $ParallelXUnitTestResultsFile = "$(System.ArtifactsDirectory)\xunit\ParallelXUnitTestResults.xml"
+      $xUnitTestResultsFile = "$(System.ArtifactsDirectory)\xunit\xUnitTestResults.xml"
 
-      Test-XUnitTestResults -TestResultsFile $ParallelXUnitTestResultsFile
+      Test-XUnitTestResults -TestResultsFile $xUnitTestResultsFile
     displayName: Test
     condition: succeeded()
diff --git a/build.psm1 b/build.psm1
index 1d0122bd225..5a8d81780c5 100644
--- a/build.psm1
+++ b/build.psm1
@@ -1374,7 +1374,7 @@ function Test-PSPesterResults
 
 function Start-PSxUnit {
     [CmdletBinding()]param(
-        [string] $ParallelTestResultsFile = "ParallelXUnitResults.xml"
+        [string] $xUnitTestResultsFile = "xUnitResults.xml"
     )
 
     # Add .NET CLI tools to PATH
@@ -1420,23 +1420,15 @@ function Start-PSxUnit {
             }
         }
 
-        dotnet build --configuration $Options.configuration
-
-        if (Test-Path $ParallelTestResultsFile) {
-            Remove-Item $ParallelTestResultsFile -Force -ErrorAction SilentlyContinue
+        if (Test-Path $xUnitTestResultsFile) {
+            Remove-Item $xUnitTestResultsFile -Force -ErrorAction SilentlyContinue
         }
 
-        # we are having intermittent issues on macOS with these tests failing.
-        # VSTS has suggested forcing them to be sequential
-        if($env:TF_BUILD -and $IsMacOS)
-        {
-            Write-Log 'Forcing parallel xunit tests to run sequentially.'
-            dotnet test -p:ParallelizeTestCollections=false --configuration $Options.configuration --no-restore --no-build --test-adapter-path:. "--logger:xunit;LogFilePath=$ParallelTestResultsFile"
-        } else {
-            dotnet test --configuration $Options.configuration --no-restore --no-build --test-adapter-path:. "--logger:xunit;LogFilePath=$ParallelTestResultsFile"
-        }
+        # We run the xUnit tests sequentially to avoid race conditions caused by manipulating the config.json file.
+        # xUnit tests run in parallel by default. To make them run sequentially, we need to define the 'xunit.runner.json' file.
+        dotnet test --configuration $Options.configuration --test-adapter-path:. "--logger:xunit;LogFilePath=$xUnitTestResultsFile"
 
-        Publish-TestResults -Path $ParallelTestResultsFile -Type 'XUnit' -Title 'Xunit Parallel'
+        Publish-TestResults -Path $xUnitTestResultsFile -Type 'XUnit' -Title 'Xunit Sequential'
     }
     finally {
         Pop-Location
diff --git a/test/xUnit/xUnit.tests.csproj b/test/xUnit/xUnit.tests.csproj
index 11704265ae9..227405930ea 100644
--- a/test/xUnit/xUnit.tests.csproj
+++ b/test/xUnit/xUnit.tests.csproj
@@ -27,4 +27,12 @@
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <PackageReference Include="XunitXml.TestLogger" Version="2.1.26" />
   </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="xunit.runner.json">
+      <Link>xunit.runner.json</Link>
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+    </Content>
+  </ItemGroup>
 </Project>
diff --git a/test/xUnit/xunit.runner.json b/test/xUnit/xunit.runner.json
new file mode 100644
index 00000000000..f5cdb055132
--- /dev/null
+++ b/test/xUnit/xunit.runner.json
@@ -0,0 +1,3 @@
+{
+  "parallelizeTestCollections": false
+}
diff --git a/tools/ci.psm1 b/tools/ci.psm1
index 26c0718730a..1034124b954 100644
--- a/tools/ci.psm1
+++ b/tools/ci.psm1
@@ -288,17 +288,17 @@ function Invoke-CIxUnit
         throw "CoreCLR pwsh.exe was not built"
     }
 
-    $ParallelXUnitTestResultsFile = "$pwd\ParallelXUnitTestResults.xml"
+    $xUnitTestResultsFile = "$pwd\xUnitTestResults.xml"
 
-    Start-PSxUnit -ParallelTestResultsFile $ParallelXUnitTestResultsFile
+    Start-PSxUnit -xUnitTestResultsFile $xUnitTestResultsFile
     Write-Host -ForegroundColor Green 'Uploading PSxUnit test results'
-    Update-TestResults -resultsFile $ParallelXUnitTestResultsFile
-    Push-Artifact -Path $ParallelXUnitTestResultsFile -name xunit
+    Update-TestResults -resultsFile $xUnitTestResultsFile
+    Push-Artifact -Path $xUnitTestResultsFile -name xunit
 
     if(!$SkipFailing.IsPresent)
     {
         # Fail the build, if tests failed
-        Test-XUnitTestResults -TestResultsFile $ParallelXUnitTestResultsFile
+        Test-XUnitTestResults -TestResultsFile $xUnitTestResultsFile
     }
 }
 
@@ -768,10 +768,10 @@ function Invoke-LinuxTests
     }
 
     try {
-        $ParallelXUnitTestResultsFile = "$pwd/ParallelXUnitTestResults.xml"
-        Start-PSxUnit -ParallelTestResultsFile $ParallelXUnitTestResultsFile
+        $xUnitTestResultsFile = "$pwd/xUnitTestResults.xml"
+        Start-PSxUnit -xUnitTestResultsFile $xUnitTestResultsFile
         # If there are failures, Test-XUnitTestResults throws
-        Test-XUnitTestResults -TestResultsFile $ParallelXUnitTestResultsFile
+        Test-XUnitTestResults -TestResultsFile $xUnitTestResultsFile
     } catch {
         $result = "FAIL"
         if (!$resultError)