This thread was archived. Please ask a new question if you need help.
Error I rebooted, shut down & restarted, uninstalled and reinstalled Firefox still get this:...Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.
Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.
Every time Firefox opened
about 2 weeks ago & now I have to use Explorer UGH!!!
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; hc; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
All Replies (1)
Kill Application In Task Manager, does firefox.exe show in the Processes tab? See: Kill Application
Causes and solutions for Firefox hanging at exit: Firefox hangs or is not responding - How to fix Firefox hangs at exit (Mozillazine article) "Firefox is already running but is not responding" error - How to fix
Safe Mode You may need to use Troubleshoot Firefox issues using Safe Mode (click on "Safe Mode" and read) to localize the problem. Firefox SafeMode is a diagnostic mode that disables extensions and some other features of Firefox. If you are using a theme, switch to the DEFAULT theme: Tools > Add-ons > Themes before starting Safe Mode. When entering Safe Mode, do not check any items on the entry window, just click "Continue in Safe Mode". Test to see if the problem you are experiencing is corrected.
See: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems Troubleshoot and diagnose Firefox problems
If the problem does not occur in Safe-mode then disable all of your extensions and then try to find which is causing it by enabling one at a time until the problem reappears. You have to close and restart Firefox after each change via File > Restart Firefox (on Mac: Firefox > Quit). You can use "Disable all add-ons" on the Safe mode start window.