I'm having a strange problem with Firefox 3.5.8 on Win7 x64. If I start Firefox and close it, and then later want to start it again, the little icon in the task bar gets its highlighted background for a few seconds, then it disappears and no firefox window appears.

I have checked this against Task Manager, and found that the earlier process is still running - in the list is an entry for "Firefox *32", which usually is taking up around 200,000 K private working memory. If I kill that process, I can start firefox normally without problems.

Why doesn't this process die when I exit firefox? Is there anything I can do to "automagically" kill it, either right after exit, or right before starting a new instance, so I don't have to go into task manager every time?

I have now discovered that this does not only prevent me from opening new instances of the program when I have closed it - it also prevents some popups, if they require opening in a window and not just in a new tab. In that case, killing the current process is not an option, since I don't want to be limited to one firefox window at a time.

I experience the same problems if I try to start a second window with the first still open, by right-clicking the icon in the task bar and selecting "Mozilla Firefox".

For some reason, Firefox is preventing me from opening a new window, if there is already a firefox process running - regardless of whether I already have a window open or not.


A lot of times this is also caused by an installed extension not stopping properly, causing Firefox to hang during closing. Check your list of installed Firefox extensions and disable them one at a time until you track down one which is preventing Firefox from closing fully.

See Here

  • Good catch! Turns out an add-on that my girlfriends printer installed was the issue. HP - sigh... – Tomas Aschan Mar 10 '10 at 22:39

I had this happen to me too quite a few times when i used Firefox. I always removed the profile and created a new one. You can read how to do this here:


Do note that removing a complete profile also deletes:

  • bookmarks
  • passwords
  • user preferences
  • etc.

So make sure to create backups before doing so!


On my machine it was the "Symantec Intrusion Prevention - 5" extension that was causing firefox to hang when closing. I simply disabled it and restarted firefox and it now closes properly.


Usually, FFox uses too much memory :(. try "End Process Tree" in the task manager and like to advise to use CProcess

  • Was this really an answer to the question, or did I miss something here? Obviously the Firefox GUI has crashed, but not the Firefox process. – TFM Mar 10 '10 at 19:05
  • @TFM: Not really "crashed" in the fatal sense - it "crashes" because I click the little x in the top right corner... So I actually want to close it, but albeit the GUI is closed, the process is not. Also, please see my edit. – Tomas Aschan Mar 10 '10 at 19:09
  • Tomas: I was criticizing mgpyone's answer. Whether Firefox uses "too much memory" or not is hardly an answer to your question. – TFM Mar 10 '10 at 19:28

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