I use Firefox for automated screenshots in a xvfb-virtual desktop. There is no mouse. So I need to reset Firefox from the commandline. Uninstall an re-install leads to the "reset-Window" again. I use Ubuntu 13.04 Server-Edition.
Solved! Go to Solution.
firefox -safemode or -safe-mode
then a new window should show to enter safe mode or Reset, hit the right keyboard key, and press enter on "Reset Firefox". No mouse needed.
Open the Command Prompt:
Windows Vista: Click on the Start Menu, click on All Programs, click on the Mozilla Firefox folder and click on Mozilla Firefox (Safe Mode).
Windows XP and Earlier: Click on the Start Menu, click on All Programs, click on the Mozilla Firefox folder and click on Mozilla Firefox (Safe Mode).
In the Firefox Safe Mode window, check the Reset all user preferences to Firefox defaults box and click on Make Changes and Restart.
Firefox will automatically restart and your settings will be reset to defaults.
Thanks @Waka_Flock_Flame, but I have no keyboard either. It's an server and xvfb is just a virtual X-Server.
Thanks @Mohammed.samad, but I use Linux.
You may have to check the ~/.cache/mozilla/firefox folder as well that current Firefox versions use for the disk cache.