Firefox is still running. Erm, no it aint!

I've stumbled across this annoying problem with Firefox a few times over the years.  The one where you close Firefox, go to open it again and it pops up with an annoying dialog explaining "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."   Restart my system?   Nope, don't think so!

It's the same every time. When I check Windows Task Manager, the Firefox process is nowhere to be seen - despite the dialog claiming it is still a running process.  After a bit of investigation (using Google Chrome!  Lol) I found out that a Firefox profile can sometimes be locked out and, therefore, when you try to reopen the application, it thinks that it's still running and will not open a new instance of Firefox.  Apparently, in Windows, there is a file called parent.lock contained within your Firefox profile folder (c:/Users/<yourname>/AppData/Roaming/Mozilla/Firefox/Profiles/<some_profile_name>/) which, if deleted, will unlock Firefox.  However, when I checked, this file didn't exist anywhere so I decided to try a little experiment of my own and it seems to work.

Basically, all I did was:

• Changed one of the characters of the profile directory folder (e.g oc3wen25.default changed to oc3wen26.default)
• Opened the profiles configuration file in the root of the Firefox app data directory (c:/Users/<yourname>/AppData/Roaming/Mozilla/Firefox/) and changed the profile name in the Path entry of this file to reflect the other name change I made.
• Saved the file and tried opening Firefox again.  It worked!  A genius, so I am...

By doing this it saved me from having to restart my machine and now I know I'll never be screwed by this problem again.  I felt I had to share this as I know how annoying it can be.

Bye for now.