Firefox is already running, but is not responding

‹ Command line replacement for gitk --all and GitX | What is librarian-puppet? ›

If your computer crashes while firefox is running, it's possible that you will get an error message like this when you next start up firefox after rebooting:

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.

To fix it, you can remove the lock files inside your profile.  On Linux (with a default setup where you have a single firefox profile) this looks something like:

rm -f $HOME/.mozilla/firefox/*/.parentlock $HOME/.mozilla/firefox/*/lock

Subscribe to All Posts - Wesley Tanaka