Thread: Firefox does not start after reinstall

The solution is simple; you will just need to delete a single particular file.

o Exit Firefox. Press [Ctrl]+[Alt]+[Del], then go to "Processes" tab and kill an executable called "firefox.exe".

o Go to the Firefox installation folder [by default C:\Program Files\Mozilla Firefoxl and delete a file there called "xpicleanup.exe" or "xpicleanup.
dat". This should set things right, and Firefox should now start normally.