diff --git a/browser/base/content/browser-plugins.js b/browser/base/content/browser-plugins.js
index 40daca47bf..769ac6d8af 100644
--- a/browser/base/content/browser-plugins.js
+++ b/browser/base/content/browser-plugins.js
@@ -182,6 +182,8 @@ var gPluginHandler = {
 
     let shouldShowNotification = false;
     let browser = gBrowser.getBrowserForDocument(doc.defaultView.top.document);
+    if (!browser)
+      return;
 
     switch (eventType) {
       case "PluginCrashed":