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Your Firefox is out of date and may contain a security risk!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

How to diagnose the cause of Firefox freezing/hanging on Mac

  • No replies
  • 14 have this problem

I found an issue, but I need help diagnosing the exact steps to re-create the issue suitable for a bug report. In this case, Firefox 16/17 is freezing (spinning beach ball, 100% CPU load on one of the cores) upon start-up when trying to restore a set of tabs. If I kill FF 16/17 then launch FF 18/19/20 (Beta/Aurora/Nightly) everything loads fine.

I've used Safe Mode to turn off extensions and plugins. I've also tried resetting the browser. But no luck. I also tried putting all of the tabs into unloaded tab groups (so that only the default "New Tab" tab opens upon startup). Surprisingly, even a blank "New Tab" didn't prevent the browser from freezing.

So, does anyone know of some way to get FF to verbosely generate debug output on the console (or perform some other tracing method) in order to deduce the cause?

Additional System Details

Installed Plug-ins

  • Shockwave Flash 11.5 r502
  • The Google Earth Plugin allows you to view 3D imagery and terrain in your web browser.
  • Version
  • Google Talk Plugin Video Accelerator version:
  • Displays Java applet content, or a placeholder if Java is not installed.
  • 5.1.10411.0


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

More Information