Firefox Is Already Running or Profile In Use Error

If you regularly use Firefox, chances are you've come across the "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system" or "Firefox cannot use the profile <profile name> because it is in use. To continue, close the running instance of Firefox or choose a different profile" errors. If you freak out when this happens and have no idea what to do just read below for some tips on fixing these errors.

If Firefox freezes up or crashes and you get the "Firefox is already running" error, try re-booting to fix the issue or give your keyboard the three finger salute (Ctrl + Alt + Del) and end the firefox.exe process.

If you get the "Profile is already in use" error your going to have to hunt down the lock file.

• 2000/XP Users look under:
  C:\Documents and Settings\ <username> \Application Data\Mozilla\Firefox\Profiles
• Vista Users look under:
  C:\Users\ <username> \AppData\Roaming\Mozilla\Firefox\Profiles\

Once your in the profile folder, delete the parent.lock file and you should be set.