"A copy of Firefox is already open. Only one copy of Firefox can be open at a time."
- by Isaac Waller
I cannot start Firefox on my Mac. It just says "A copy of Firefox is already open. Only one copy of Firefox can be open at a time." I have tried restarting the computer. Any fixes?
You have suggested deleting the lock files in my profile, but, I don't have a profile. I was trying to fix the problem in question http://superuser.com/questions/3275/firefox-on-mac-slow-slow-slow by deleting my profile, so I deleted it, and this came up. So I cannot delete the lock files because they don't exist.