diff --git a/user/src/com/google/gwt/resources/rebind/context/MhtmlClientBundleGenerator.java b/user/src/com/google/gwt/resources/rebind/context/MhtmlClientBundleGenerator.java
index 4ca979a..984b42d 100644
--- a/user/src/com/google/gwt/resources/rebind/context/MhtmlClientBundleGenerator.java
+++ b/user/src/com/google/gwt/resources/rebind/context/MhtmlClientBundleGenerator.java
@@ -31,6 +31,7 @@
 public class MhtmlClientBundleGenerator extends AbstractClientBundleGenerator {
 
   private static final String BUNDLE_EXTENSION = ".cache.txt";
+  private static int counter = 0;
 
   private MhtmlResourceContext resourceContext;
   private String partialPath;
@@ -42,10 +43,15 @@
         resourceBundleType);
 
     /*
+     * We use a counter to ensure that the generated resources have unique
+     * names. Previously we used the system time, but it sometimes led to non-
+     * unique names if subsequent calls happened within the same millisecond.
+     * 
      * TODO: figure out how to make the filename stable based on actual content.
      */
+    counter++;
     partialPath = Util.computeStrongName(Util.getBytes(resourceBundleType.getQualifiedSourceName()
-        + System.currentTimeMillis()))
+        + counter))
         + BUNDLE_EXTENSION;
     resourceContext.setPartialPath(partialPath);