Index: Core/Common/test/Core.Common.TestUtil/FileDisposeHelper.cs
===================================================================
diff -u -rc899baf08791f622f518d4cc84ed5a6e27aac4c5 -r60e3be16f43b477edc645964439415f9552a9bef
--- Core/Common/test/Core.Common.TestUtil/FileDisposeHelper.cs	(.../FileDisposeHelper.cs)	(revision c899baf08791f622f518d4cc84ed5a6e27aac4c5)
+++ Core/Common/test/Core.Common.TestUtil/FileDisposeHelper.cs	(.../FileDisposeHelper.cs)	(revision 60e3be16f43b477edc645964439415f9552a9bef)
@@ -166,7 +166,7 @@
         /// <exception cref="ArgumentException">Thrown when the file could not be created by the system.</exception>
         private void Create()
         {
-            foreach (string filePath in filePathStreams.Keys)
+            foreach (string filePath in filePathStreams.Keys.ToArray())
             {
                 CreateFile(filePath);
             }