User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:40.0) Gecko/20100101 Firefox/40.0 Build ID: 20150807085045 Steps to reproduce: Whenever starting Firefox 40.0.2 on Macbook Pro running 10.7.5 Firefox would seem fine, but when switching to another tab or trying to do anything would cause Firefox to freeze with Mac's spinning pinwheeel and would stay frozen. Actual results: I've tried closing tabs, starting in Safe Mode, refreshing Firefox, reinstalling Firefox, nothing solved the problem until I DOWNGRADED to Firefox 39.0.3! Then Firefox ran perfectly. Expected results: It can't be a plugin issue since I tried running Firefox in Safe Mode, so the issue is version 40.0.2 of FF!
Would you be able to run the mozregression tool at http://mozilla.github.io/mozregression/ to narrow down the range of what caused this problem? There were a lot of changes between 39 and 40 and it will be hard to identify the problem without a better idea of when it was introduced. Thanks!
Does it happen with Version 41 started in safe mode? https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
Closing this as incomplete due to the inability to reproduce and lack of follow-up information. Mike, if you return to this bug and can still reproduce it, please feel free to add more information so we can hopefully reproduce the issue and reopen the bug.
reporter writes "Since Firefox has been updated, problem has been solved!"