After I close Firefox 4.0 and try to open it later, it says that another instance of firefox is already open and won't let me open firefox. I have to restart computer..
After it closes I work on another program, etc. When I try to go online again firefox says it's still open even though I can see nothing. Going to Task Manager doesn't show anything open. I'm running Windows 7 64-bit.
All Replies (1)
https://support.mozilla.com/en-US/kb/Firefox%20hangs
See hang-at-exit