I’ve been adding and removing a lot of add-ons to Firefox. Recently it started bugging out and wouldn’t load several websites properly. So I did all the usual things I would do in a situation like this: cleared all the cache, tried disabling add-ons, restart Firefox, etc.
None of those worked so I decided to reset Firefox to the factory default settings. Here is how you do it:
Windows:
firefox -safe-mode
"C:\Program Files\Mozilla Firefox\firefox.exe" -safe-mode
Linux:
/path/to/firefox/firefox -safe-mode
Mac OS X:
/Applications/Firefox.app/Contents/MacOS/firefox -safe-mode
If you installed Firefox to a location other than the default location, modify your path as necessary.

You should know you are in Safe Mode and able to reset Firefox to factory defaults when you see a window called Firefox safe mode. The Firefox safe mode window will contain several options useful for restoring or resetting Firefox to the factory presets.
February 27th, 2008 at 2:35 pm
Wow, that was easy… and fixed my Firefox too!
I was having alot problems with some websites too,
probably same reason like yours, installed too many add ons….
Thanks a ton!!!!