diff --git a/src/Extensions/ParallelForEachExtensions.cs b/src/Extensions/ParallelForEachExtensions.cs
index 4c7d7f8..fa20ccf 100644
--- a/src/Extensions/ParallelForEachExtensions.cs
+++ b/src/Extensions/ParallelForEachExtensions.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -76,11 +77,12 @@ public List<Exception> ReadExceptions()
                     _exceptionListLock.Enter(ref lockTaken);
                 try
                 {
-                    return _exceptionList;
+                    // Return a copy, so the list being returned will not be modified
+                    // by tasks that are still running if the loop was canceled
+                    return new List<Exception>(_exceptionList ?? Enumerable.Empty<Exception>());
                 }
                 finally
                 {
-                    _exceptionList = null;
                     _exceptionListLock.Exit(useMemoryBarrier: false);
                 }
             }