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firefox says it's already running but it isn't!


Error message says: '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.;

I checked task manager and nothing to do with firefox is running.

I restarted and no effect.

I uninstalled and reinstalled to no effect. no viruses that I know of

Chosen solution

Maybe your xxxxxx.default folder is deleted.

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Additional System Details


  • User Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C)

More Information

xr417 38 solutions 195 answers

Chosen Solution

Maybe your xxxxxx.default folder is deleted.

Question owner

Actually I managed to sort it by uninstalling and deleting all personal options (instead of carrying them over) and reinstalling. Not sure what the problem was but working now

  • Moderator
30 solutions 273 answers

Locate your profile directory. See if there is a file named 'parent.lock, if so, delete it. If this doesn't work, try rebooting your computer. Still doesn't work? Hold down the shift key when starting Firefox, this is safe_mode. If it starts ok then you may have an extension(s) that are causing the problem. Post back to let us know if anything fixed it or not.

JimDirt 1 solutions 9 answers

Mine says the same error message except it does not say it is not responding , just open , but it wont let me open , it just gives the message every time i TRY to open it

This just started doing this today , but it has done it 3 times , i have also noticed that my mouse wont scroll sometimes , i will be on a webpage and its like the page is locked , but if i move the page by the slider on the right manually , then the mouse scroll works again , this also just started tonight , so i am guessing the 2 are related , and i get no other system errors , or anything i can find running in the background , when i do get it to allow me to open it again , the pages stop freezing , till the next time , then the next time i try to open Firefox , i get the error , so the mouse scroll freeze and the error must be related somehow