Tap here to go to the mobile version of the site.
Your Firefox is out of date and may contain a security risk! Upgrade Firefox

Support Forum

FF becomes unresponsive if minimised in dock/ left idle.


I'm running Mountain Lion on a 2009 Intel MacBook Pro. Since upgrading to Firefox 18.0.1 a few days ago, my system, at times, becomes unusable:

- when active, Firefox is clean, supple and very fluid. - when left idle (background) or minimised to the dock for a short length of time, it becomes unresponsive. - this then has a knock-on effect on my system and renders it unusable:

 - on awaking the system/ Firefox, a significant lag/ hang of around 30-40 seconds is experienced
 - this is accompanied by the «beachball», and occasionally, the blue beachball.
 - it seems as though excessive RAM is being consumed, but on checking Activity Monitor, all seems correct.
 - it gets to a stage where the lag/ hang is so bad that other apps refuse to coöperate

- the only work around I have found for the time being is a force quit (which shows that Firefox has become unresponsive - a little like a crash, but caused by no activity).

I wonder if anyone else has the same/ a similar problem. What fixes you use. If it is a known bug. If anyone has managed to rectify the situation.

Additional System Details

Installed Plug-ins

  • Displays Java applet content, or a placeholder if Java is not installed.
  • Shockwave Flash 11.5 r502
  • Microsoft Office for Mac SharePoint Browser Plug-in
  • Ce module vous permet de visualiser le contenu multimédia de nombreux sites web. Pour en savoir plus, consultez le site QuickTime.


  • User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:18.0) Gecko/20100101 Firefox/18.0

More Information

finitarry 157 solutions 2177 answers

I see something similar on Mac OS 10.6. If Firefox is running and I leave the computer idle long enough it to run the screen saver and then go to sleep, quite often Firefox will not respond when I try to do anything with it after the computer wakes up. In fact, quite often the entire computer will be unresponsive.