diff --git a/browser/base/content/aboutDialog.js b/browser/base/content/aboutDialog.js
index dd9478b998132..853d568c68d41 100644
--- a/browser/base/content/aboutDialog.js
+++ b/browser/base/content/aboutDialog.js
@@ -40,6 +40,8 @@
 // Services = object with smart getters for common XPCOM services
 Components.utils.import("resource://gre/modules/Services.jsm");
 
+const PREF_EM_HOTFIX_ID = "extensions.hotfix.id";
+
 function init(aEvent)
 {
   if (aEvent.target != document)
@@ -378,6 +380,11 @@ appUpdater.prototype =
    * Checks the compatibility of add-ons for the application update.
    */
   checkAddonCompatibility: function() {
+    try {
+      var hotfixID = Services.prefs.getCharPref(PREF_EM_HOTFIX_ID);
+    }
+    catch (e) { }
+
     var self = this;
     AddonManager.getAllAddons(function(aAddons) {
       self.addons = [];
@@ -402,9 +409,10 @@ appUpdater.prototype =
         // incompatible. If an addon's type equals plugin it is skipped since
         // checking plugins compatibility information isn't supported and
         // getting the scope property of a plugin breaks in some environments
-        // (see bug 566787).
+        // (see bug 566787). The hotfix add-on is also ignored as it shouldn't
+        // block the user from upgrading.
         try {
-          if (aAddon.type != "plugin" &&
+          if (aAddon.type != "plugin" && aAddon.id != hotfixID &&
               !aAddon.appDisabled && !aAddon.userDisabled &&
               aAddon.scope != AddonManager.SCOPE_APPLICATION &&
               aAddon.isCompatible &&
diff --git a/toolkit/mozapps/extensions/content/update.js b/toolkit/mozapps/extensions/content/update.js
index 393548c53f5bc..3e664c70d4cfe 100644
--- a/toolkit/mozapps/extensions/content/update.js
+++ b/toolkit/mozapps/extensions/content/update.js
@@ -42,6 +42,7 @@
 
 const PREF_UPDATE_EXTENSIONS_ENABLED            = "extensions.update.enabled";
 const PREF_XPINSTALL_ENABLED                    = "xpinstall.enabled";
+const PREF_EM_HOTFIX_ID                         = "extensions.hotfix.id";
 
 Components.utils.import("resource://gre/modules/Services.jsm");
 Components.utils.import("resource://gre/modules/AddonManager.jsm");
@@ -159,10 +160,15 @@ var gVersionInfoPage = {
                                   "nextButtonText", true,
                                   "cancelButtonText", false);
 
+    try {
+      var hotfixID = Services.prefs.getCharPref(PREF_EM_HOTFIX_ID);
+    }
+    catch (e) { }
+
     // Retrieve all add-ons in order to sync their app compatibility information
     AddonManager.getAllAddons(function(aAddons) {
       gUpdateWizard.addons = aAddons.filter(function(a) {
-        return a.type != "plugin";
+        return a.type != "plugin" && a.id != hotfixID;
       });
 
       gVersionInfoPage._totalCount = gUpdateWizard.addons.length;
diff --git a/toolkit/mozapps/update/content/updates.js b/toolkit/mozapps/update/content/updates.js
index 1b9478c3b538b..7ddd9cf0f07d6 100644
--- a/toolkit/mozapps/update/content/updates.js
+++ b/toolkit/mozapps/update/content/updates.js
@@ -60,6 +60,8 @@ const PREF_APP_UPDATE_NEVER_BRANCH       = "app.update.never.";
 const PREF_APP_UPDATE_TEST_LOOP          = "app.update.test.loop";
 const PREF_PLUGINS_UPDATEURL             = "plugins.update.url";
 
+const PREF_EM_HOTFIX_ID                  = "extensions.hotfix.id";
+
 const UPDATE_TEST_LOOP_INTERVAL     = 2000;
 
 const URI_UPDATES_PROPERTIES  = "chrome://mozapps/locale/update/updates.properties";
@@ -521,6 +523,11 @@ var gUpdates = {
       return;
     }
 
+    try {
+      var hotfixID = Services.prefs.getCharPref(PREF_EM_HOTFIX_ID);
+    }
+    catch (e) { }
+
     var self = this;
     AddonManager.getAllAddons(function(addons) {
       self.addons = [];
@@ -544,9 +551,10 @@ var gUpdates = {
         // incompatible. If an addon's type equals plugin it is skipped since
         // checking plugins compatibility information isn't supported and
         // getting the scope property of a plugin breaks in some environments
-        // (see bug 566787).
+        // (see bug 566787). The hotfix add-on is also ignored as it shouldn't
+        // block the user from upgrading.
         try {
-          if (addon.type != "plugin" &&
+          if (addon.type != "plugin" && addon.id != hotfixID &&
               !addon.appDisabled && !addon.userDisabled &&
               addon.scope != AddonManager.SCOPE_APPLICATION &&
               addon.isCompatible &&
diff --git a/toolkit/mozapps/update/nsUpdateService.js b/toolkit/mozapps/update/nsUpdateService.js
index b2ec5e134e8b8..9bc1f4b3c1375 100644
--- a/toolkit/mozapps/update/nsUpdateService.js
+++ b/toolkit/mozapps/update/nsUpdateService.js
@@ -86,6 +86,8 @@ const PREF_PARTNER_BRANCH                 = "app.partner.";
 const PREF_APP_DISTRIBUTION               = "distribution.id";
 const PREF_APP_DISTRIBUTION_VERSION       = "distribution.version";
 
+const PREF_EM_HOTFIX_ID                   = "extensions.hotfix.id";
+
 const URI_UPDATE_PROMPT_DIALOG  = "chrome://mozapps/content/update/updates.xul";
 const URI_UPDATE_HISTORY_DIALOG = "chrome://mozapps/content/update/history.xul";
 const URI_BRAND_PROPERTIES      = "chrome://branding/locale/brand.properties";
@@ -1657,6 +1659,11 @@ UpdateService.prototype = {
   },
 
   _checkAddonCompatibility: function AUS__checkAddonCompatibility() {
+    try {
+      var hotfixID = Services.prefs.getCharPref(PREF_EM_HOTFIX_ID);
+    }
+    catch (e) { }
+
     // Get all the installed add-ons
     var self = this;
     AddonManager.getAllAddons(function(addons) {
@@ -1681,9 +1688,10 @@ UpdateService.prototype = {
         // incompatible. If an addon's type equals plugin it is skipped since
         // checking plugins compatibility information isn't supported and
         // getting the scope property of a plugin breaks in some environments
-        // (see bug 566787).
+        // (see bug 566787). The hotfix add-on is also ignored as it shouldn't
+        // block the user from upgrading.
         try {
-          if (addon.type != "plugin" &&
+          if (addon.type != "plugin" && addon.id != hotfixID &&
               !addon.appDisabled && !addon.userDisabled &&
               addon.scope != AddonManager.SCOPE_APPLICATION &&
               addon.isCompatible &&
diff --git a/toolkit/mozapps/update/test/chrome/utils.js b/toolkit/mozapps/update/test/chrome/utils.js
index edbb262c8797e..d870873248390 100644
--- a/toolkit/mozapps/update/test/chrome/utils.js
+++ b/toolkit/mozapps/update/test/chrome/utils.js
@@ -146,12 +146,13 @@ const ADDON_PREP_DIR = "appupdateprep";
 // Preference for storing add-ons that are disabled by the tests to prevent them
 // from interefering with the tests.
 const PREF_DISABLEDADDONS = "app.update.test.disabledAddons";
+const PREF_EM_HOTFIX_ID = "extensions.hotfix.id";
 const TEST_ADDONS = [ "appdisabled_1", "appdisabled_2",
                       "compatible_1", "compatible_2",
                       "noupdate_1", "noupdate_2",
                       "updatecompatibility_1", "updatecompatibility_2",
                       "updateversion_1", "updateversion_2",
-                      "userdisabled_1", "userdisabled_2" ];
+                      "userdisabled_1", "userdisabled_2", "hotfix" ];
 
 
 const TEST_TIMEOUT = 25000; // 25 seconds
@@ -817,6 +818,7 @@ function setupPrefs() {
   Services.prefs.setIntPref(PREF_APP_UPDATE_IDLETIME, 0);
   Services.prefs.setIntPref(PREF_APP_UPDATE_PROMPTWAITTIME, 0);
   Services.prefs.setBoolPref(PREF_EXTENSIONS_STRICT_COMPAT, true);
+  Services.prefs.setCharPref(PREF_EM_HOTFIX_ID, "hotfix" + ADDON_ID_SUFFIX);
 }
 
 /**
@@ -918,6 +920,10 @@ function resetPrefs() {
   if (Services.prefs.prefHasUserValue(PREF_EXTENSIONS_STRICT_COMPAT)) {
 		Services.prefs.clearUserPref(PREF_EXTENSIONS_STRICT_COMPAT);
   }
+
+  if (Services.prefs.prefHasUserValue(PREF_EM_HOTFIX_ID)) {
+    Services.prefs.clearUserPref(PREF_EM_HOTFIX_ID);
+  }
 }
 
 /**