Recently, every time I started Firefox it was taking a long time to load and before I could see a Firefox window it suddenly crashed. I tried to check the RAM and hard disk for problems, but everything else was working fine. I also tried to uninstall Firefox and reinstall a freshly downloaded copy of Firefox in Windows, but it did not work either. Finally a co-worker told me a little trick that helped me fix Firefox startup crash problem instantly.
Apparently, Firefox was crashing at startup because there was file corruption in the Firefox profiles folder. You can of course delete the whole profiles folder and create a new profile, but this way you will end up losing all of your saved bookmarks, Firefox settings and installed extensions. A much neater way is to delete only those possible files that could be causing Firefox to crash at startup. Here is how you can delete these files and make Firefox run again faster and without any problems:
- Press Win+R hotkey to open the Run dialog, type %LocalAppData% in the Run dialog and press Enter.
- This will open the Local AppData folder for your Windows user profile. Inside this folder, open the sub-folder Mozilla\Firefox\Profiles. There you will find a profile folder with name ending in .default.
- Open this profile folder and you will find many sub-folders. Select and delete the folders named cache2, jumpListCache, OfflineCache and startupCache.
- Now try starting Firefox, it should load quicker and should not crash this time.
This method should be used weekly or monthly to make Firefox load faster and to prevent any cache corruption related problems. Of course, if Firefox can be launched then you can clear the cache from within the Firefox. But in case Firefox is crashing and cannot be used, then you have to manually delete the cache as explained.