How To Fix The 'Firefox Is Already Running' Issue

I don't know about you, about more often than not, when I go to start Firefox, it tells me that Firefox is already running and I can't start it.  It's pretty annoying.  The same kind of annoying when ALL my Logitech Marble Mouse(s) seem to have a click and hold issue.  (But that's something for another day)

I found out how to fix this "Firefox already running issue:"

For me, I open up the Task Manager (R-click a blank spot on the running apps bar, and choose 'Task Manager' from the options.) Or press ctrl+shift+esc all at once.

Go to the "Processes" tab.

Click on "Image Name" in the left column.  This is alphabetizing the process names running.  (It might be called Processes or some other name than Image, like I have on my system.  But it's usually the left-most column.)

Find Firefox in the list of apps running,

Highlight it,

Click "End Process" button in the lower right.

I usually only have one instance of the application running, but if you have more than one, then kill them all.


That clears the application out of the way.

No, we are not done, because the fact that the application is still running (Which is something I've seen on all my systems), means that the app is having an issue with a locked profile file.

While Firefox is not running,

Go to the "Run" command and type in


And hit "OK" or what ever button there is there for you, depending on your OS.

This should take you to your browser app folder.

There should be a folder in this location with the word "*.default-*" in it.  (I had two, but one was empty, so I smite the empty one altogether.)

Go into the folder that has lots of stuff in it, find your parent.lock file and delete it.

THIS, is what Mozilla says will fix your issue.

We'll see about that!!!