diff --git a/mozilla/mail/app/profile/all-thunderbird.js b/mozilla/mail/app/profile/all-thunderbird.js
index 492db81d32e..437afa3b60b 100644
--- a/mozilla/mail/app/profile/all-thunderbird.js
+++ b/mozilla/mail/app/profile/all-thunderbird.js
@@ -51,15 +51,24 @@ pref("update.app.url", "chrome://mozapps/locale/update/update.properties");
 pref("update.extensions.enabled", true);
 
 // App-specific update preferences
-pref("app.update.logEnabled", true);
-pref("app.update.enabled", false);               // Whether or not app updates are enabled
 
-// Whether or not automated background app updates are enabled.
-pref("app.update.autoInstallEnabled", true); 
-// If automatic download is enabled, whether or not the Update system should 
-// automatically install the downloaded updates or just download them and prompt
-// the user to install.
-pref("app.update.autoInstallMode", 0);  
+// Whether or not app updates are enabled
+pref("app.update.enabled", false);               
+
+// Defines how the Application Update Service notifies the user about updates:
+//
+// AUM Set to:        Minor Releases:     Major Releases:
+// 0                  download no prompt  download no prompt
+// 1                  download no prompt  download no prompt if no incompatibilities
+// 2                  download no prompt  prompt
+// 3                  prompt              prompt
+//
+// See chart in nsUpdateService.js.in for more details
+//
+pref("app.update.mode", 1);
+// If set to true, the Update Service will present no UI for any event.
+pref("app.update.silent", false);
+pref("app.update.logEnabled", true);
 
 // Default service URL for testing.
 pref("app.update.url", "chrome://mozapps/locale/update/updates.properties");
diff --git a/mozilla/mail/base/content/mailWindowOverlay.js b/mozilla/mail/base/content/mailWindowOverlay.js
index 3ba51ceaf1b..0b53e3c1fe9 100644
--- a/mozilla/mail/base/content/mailWindowOverlay.js
+++ b/mozilla/mail/base/content/mailWindowOverlay.js
@@ -2535,12 +2535,20 @@ function buildHelpMenu()
   var um = 
       Components.classes["@mozilla.org/updates/update-manager;1"].
       getService(Components.interfaces.nsIUpdateManager);
-  var activeUpdate = um.activeUpdate;
+  
+  // 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 canUpdate = updates.canUpdate;
+  checkForUpdates.setAttribute("disabled", !canUpdate);
+  if (!canUpdate)
+    return;
 
   if (!gMessengerBundle)
     gMessengerBundle = document.getElementById("bundle_messenger");
   
   var label = gMessengerBundle.getString("updates_checkForUpdates");
+  var activeUpdate = um.activeUpdate;
   if (activeUpdate) 
   {
     if (updates.isDownloading) 
@@ -2558,15 +2566,10 @@ function buildHelpMenu()
         label = gMessengerBundle.getString("updates_resumeDownloadingFallback");
     }
   }
-    
-  var checkForUpdates = document.getElementById("checkForUpdates");
+
   checkForUpdates.label = label;
   if (um.activeUpdate && updates.isDownloading)
     checkForUpdates.setAttribute("loading", "true");
   else
     checkForUpdates.removeAttribute("loading");
-
-  // Disable the UI if the update enabled pref has been locked by the 
-  // administrator.
-  checkForUpdates.disabled = gPrefBranch.prefIsLocked("app.update.enabled");
 }
diff --git a/mozilla/mail/components/preferences/advanced.js b/mozilla/mail/components/preferences/advanced.js
index 6eb15760c31..61a05a8b1e8 100644
--- a/mozilla/mail/components/preferences/advanced.js
+++ b/mozilla/mail/components/preferences/advanced.js
@@ -74,6 +74,13 @@ var gAdvancedPane = {
   {
     var preference = document.getElementById("app.update.enabled");
     document.getElementById("enableAutoInstall").disabled = !preference.value;
+
+    var aus = 
+        Components.classes["@mozilla.org/updates/update-service;1"].
+        getService(Components.interfaces.nsIApplicationUpdateService);
+    var checkNowButton = document.getElementById("checkNowButton");
+    checkNowButton.disabled = !aus.canUpdate;
+    
     this.updateAutoInstallUI();
     return undefined;
   },
@@ -108,8 +115,9 @@ var gAdvancedPane = {
     var features = "chrome,centerscreen,dialog,titlebar";
     const URI_EXTENSION_UPDATE_DIALOG = 
       "chrome://mozapps/content/extensions/update.xul";
-    var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
-                        .getService(Components.interfaces.nsIWindowWatcher);
+    var ww = 
+        Components.classes["@mozilla.org/embedcomp/window-watcher;1"].
+        getService(Components.interfaces.nsIWindowWatcher);
     ww.openWindow(window, URI_EXTENSION_UPDATE_DIALOG, "", features, ary);  
   },
   
diff --git a/mozilla/mail/components/preferences/advanced.xul b/mozilla/mail/components/preferences/advanced.xul
index e903d7f5166..77411674fb0 100644
--- a/mozilla/mail/components/preferences/advanced.xul
+++ b/mozilla/mail/components/preferences/advanced.xul
@@ -59,7 +59,7 @@
       <preference id="mailnews.reuse_message_window" name="mailnews.reuse_message_window" type="bool"/>
       <preference id="app.update.enabled"              name="app.update.enabled"              type="bool"/>
       <preference id="app.update.autoInstallEnabled"   name="app.update.autoInstallEnabled"   type="bool"/>
-      <preference id="app.update.autoInstallMode"      name="app.update.autoInstallMode"      type="int"/>
+      <preference id="app.update.mode"                 name="app.update.mode" type="int"/>
       <preference id="extensions.update.autoUpdateEnabled"
                   name="extensions.update.autoUpdateEnabled"
                   type="bool"/>
@@ -198,7 +198,7 @@
                           accesskey="&enableAutoInstall.accesskey;"
                           preference="app.update.autoInstallEnabled"
                           onsyncfrompreference="return gAdvancedPane.updateAutoInstallUI();"/>
-                <radiogroup id="autoInstallMode" preference="app.update.autoInstallMode">
+                <radiogroup id="autoInstallMode" preference="app.update.mode">
                   <grid class="indent">
                     <columns>
                       <column/>
@@ -217,7 +217,7 @@
                 </radiogroup>
                 <separator class="thin"/>
                 <hbox>
-                  <button label="&checkNow.label;" accesskey="&appCheckNow.accesskey;"
+                  <button id="checkNowButton" label="&checkNow.label;" accesskey="&appCheckNow.accesskey;"
                           oncommand="gAdvancedPane.checkForUpdates();"
                           preference="app.update.enabled"/>
                   <button label="&showUpdates.label;" accesskey="&showUpdates.accesskey;"