diff --git a/toolkit/mozapps/extensions/test/xpinstall/browser_bug638292.js b/toolkit/mozapps/extensions/test/xpinstall/browser_bug638292.js
index e4ebb3520c6e..001434b967cc 100644
--- a/toolkit/mozapps/extensions/test/xpinstall/browser_bug638292.js
+++ b/toolkit/mozapps/extensions/test/xpinstall/browser_bug638292.js
@@ -1,16 +1,8 @@
 // ----------------------------------------------------------------------------
 // Test whether an InstallTrigger.enabled is working
-
-let prefs = Cc["@mozilla.org/preferences-service;1"]
-              .getService(Components.interfaces.nsIPrefBranch);
-let gMultiplePopupsPref;
-
 function test() {
   waitForExplicitFinish();
 
-  gMultiplePopupsPref = prefs.getBoolPref("dom.block_multiple_popups");
-  prefs.setBoolPref("dom.block_multiple_popups", false);
-
   gBrowser.selectedTab = gBrowser.addTab();
   gBrowser.selectedBrowser.addEventListener("load", function() {
     gBrowser.selectedBrowser.removeEventListener("load", arguments.callee, true);
@@ -54,7 +46,6 @@ function page_loaded() {
 
       check_load(function() {
         gBrowser.removeCurrentTab();
-        prefs.setBoolPref("dom.block_multiple_popups", gMultiplePopupsPref);
         finish();
       });
     });