On Ubuntu, When trying to open Firefox it is saying that it is already running but not responding. I am on a system where I dont have access to view the root. I have had this issue before and fixed it but I dont remember how. I know before I had to delete a file but I dont remember what or where.
Solution:
It’s probably that your profile is locked; happens on unclean shutdown sometimes.
See this support page on Mozilla.com, specifically:
pkill firefox(or restart your computer). Don’t try to start Firefox.- Go to your Firefox profile folder – see How to find your profile.
- Delete the lock file parent.lock
Your profile is in ~/.mozilla/firefox/*.default/ (the * will be a random sequence of 8 letters)
rm parent.lock and try again.