Try to start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to see if that works. *Windows: hold down the Shift key while starting Firefox *Mac: hold down the Options key while starting Firefox Create a new profile to test if your current profile is causing the problem. See "Creating a profile": *https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles *http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox ---- If you have submitted crash reports then please post the IDs of one or more recent crash reports that start with "bp-". *bp-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx You can find the report ID of recent crash reports on the "Help -> Troubleshooting Information" page (about:support). *click the "All Crash Reports" button on this page to open the <b>about:crashes</b> page and see all crash reports. Alternatively you can open about:crashes via the location/address bar. See also: *http://kb.mozillazine.org/Mozilla_Crash_Reporter *https://support.mozilla.org/kb/Mozilla+Crash+Reporter If you can't start Firefox, see: *http://kb.mozillazine.org/Mozilla_Crash_Reporter#Location_of_crash_reports *http://kb.mozillazine.org/Mozilla_Crash_Reporter#Viewing_crash_reports *https://developer.mozilla.org/How_to_get_a_stacktrace_for_a_bug_report