--- browser/base/content/utilityOverlay.js	2010-09-14 16:15:11.000000000 +0200
+++ browser/base/content/utilityOverlay.js-gil	2010-10-05 00:48:51.000000000 +0200
@@ -502,7 +502,7 @@
   // Disable the UI if the update enabled pref has been locked by the 
   // administrator or if we cannot update for some other reason
   var checkForUpdates = document.getElementById("checkForUpdates");
-  var canCheckForUpdates = updates.canCheckForUpdates;
+  var canCheckForUpdates = updates.canCheckForUpdates && updates.canApplyUpdates;
   checkForUpdates.setAttribute("disabled", !canCheckForUpdates);
   if (!canCheckForUpdates)
     return;