Fix Firefox With Last Pass Not Responding

Martin Brinkmann
Jun 10, 2010
Updated • Apr 24, 2014
Firefox, Firefox add-ons

A recent upgrade to the latest beta release of Firefox 3.6.4 from version 3.6.3 caused a stability issue where the browser would stop responding completely. The Firefox window became unresponsive and the only way to close the browser was to kill its process in Windows Explorer.

Tests with Firefox 3.7 alphas showed the exact same stability problems. Firefox would sometimes hang when it loaded tabs after start up, hang when you would use a file browser to load or save files to the local system, and also seemingly random with no apparent theme to it.

Disabling all add-ons seemed to solve the freezing issues and some further testing revealed that it was the Last Pass add-on that was responsible for the freezes in Firefox.

Note that you can either create and use a different Firefox profile to test the browser without add-ons, or run it in safe mode which you do when you hold down the Shift-key on your keyboard before you launch it on your computer system.

Several forum threads on the Last Pass forum have been created by other Firefox users who have experienced the same problems with the latest version of the password management extension.

The Last Pass developers have created a non binary version of the Firefox add-on which solved the stability problems that users were experiencing.

This add-on can simply be installed like any other Firefox add-on and will replace the existing Last Pass version in the browser. Cautious users might want to uninstall the add-on first and install the new version afterwards. The new Last Pass version can be downloaded from the official Last Pass site.

The issue has been resolved and it is no longer necessary to download that version. What may be interesting though is that the LastPass add-on on the Mozilla website is not updated as often as the extension on the company website. If you run into troubles and are able to pinpoint them to the add-on, first thing you may want to do is check out if an update has been posted on the LastPass website.


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  1. Caroldos said on August 6, 2015 at 1:44 am

    Thank you Martin for your help! I could not get Last Pass to work with newest version of Firefox, but your “fix” did wonders for me! Thanks!

  2. bf said on June 11, 2010 at 12:45 am

    Spoke too soon. Just today Firefox had an update(not sure if it was to final version as Firefox stopped showing RC versions) and Firefox(menus) stopped responding two times in last two hours.

  3. bf said on June 10, 2010 at 9:28 pm

    I had this problem on Firefox 3.6.4 beta 3 and 4, but not since then.

  4. Dougle said on June 10, 2010 at 6:52 pm

    I have to wonder if this is a clash between LP and some other extension. It seems quite rare and certainly hasn’t affected me and I’ve used LP with the nightly branch and trunk builds of fx for ages.

    1. Martin said on June 10, 2010 at 6:55 pm

      Dougle I ran Last Pass without any other add-on or plugin and Firefox still stopped responding.

  5. Roman ShaRP said on June 10, 2010 at 6:32 pm


    Experiencing this problem myself, but for now only in one of two browser instances where I’m using Lastpass. Thought it was some add-on conflict.

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