diff --git a/mozilla/browser/components/microsummaries/src/nsMicrosummaryService.js.in b/mozilla/browser/components/microsummaries/src/nsMicrosummaryService.js.in
index ecc955a00f3..4071a618904 100644
--- a/mozilla/browser/components/microsummaries/src/nsMicrosummaryService.js.in
+++ b/mozilla/browser/components/microsummaries/src/nsMicrosummaryService.js.in
@@ -688,7 +688,8 @@ MicrosummaryService.prototype = {
       
       // rebuild the bookmarks toolbar
       var bookmarksToolbar = win.document.getElementById("bookmarks-ptf");
-      bookmarksToolbar.builder.rebuild();
+      if (bookmarksToolbar)
+        bookmarksToolbar.builder.rebuild();
       
       // rebuild the bookmarks sidebar
       var sidebar = win.document.getElementById("sidebar");