diff --git a/test/Templates.Test/Helpers/TemplateTestBase.cs b/test/Templates.Test/Helpers/TemplateTestBase.cs
index 54854d6c75..f8466e1ea8 100644
--- a/test/Templates.Test/Helpers/TemplateTestBase.cs
+++ b/test/Templates.Test/Helpers/TemplateTestBase.cs
@@ -15,6 +15,8 @@ namespace Templates.Test
 {
     public class TemplateTestBase : IDisposable
     {
+        private static object DotNetNewLock = new object();
+
         protected string ProjectName { get; set; }
         protected string TemplateOutputDir { get; private set; }
         protected ITestOutputHelper Output { get; private set; }
@@ -63,7 +65,12 @@ namespace Templates.Test
                 args += $" -lang {language}";
             }
 
-            ProcessEx.Run(Output, TemplateOutputDir, DotNetMuxer.MuxerPathOrDefault(), args).WaitForExit(assertSuccess: true);
+            // Only run one instance of 'dotnet new' at once, as a workaround for
+            // https://github.com/aspnet/templating/issues/63
+            lock (DotNetNewLock)
+            {
+                ProcessEx.Run(Output, TemplateOutputDir, DotNetMuxer.MuxerPathOrDefault(), args).WaitForExit(assertSuccess: true);
+            }
         }
 
         protected void RunNpmInstall()
diff --git a/test/Templates.Test/Properties/TestAttributes.cs b/test/Templates.Test/Properties/TestAttributes.cs
deleted file mode 100644
index 69295a81d1..0000000000
--- a/test/Templates.Test/Properties/TestAttributes.cs
+++ /dev/null
@@ -1,4 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-[assembly: Xunit.CollectionBehavior(DisableTestParallelization = true)]