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Firefox won't run because it 'is already running' I have tried all steps in firefox crashes articles

David McRitchie replied
dknodel2106

I had a spectacular crash in Firefox (FF) - Malware or a virus - I think my system is clean now. I removed FF and all FF/Mozilla files, downloaded a new FF. It will not run because: "Close Firefox A copy of Firefox is already open. Only one copy of Firefox can be open at a time" I have tried all the remedies on the 'FF crashes' support page. The profile manager doesn't run probably because that was among the files I deleted. All other apps seem to run fine.

I had a spectacular crash in Firefox (FF) - Malware or a virus - I think my system is clean now. I removed FF and all FF/Mozilla files, downloaded a new FF. It will not run because: "Close Firefox A copy of Firefox is already open. Only one copy of Firefox can be open at a time" I have tried all the remedies on the 'FF crashes' support page. The profile manager doesn't run probably because that was among the files I deleted. All other apps seem to run fine.

All Replies (1)

Start with item #2

  1. close Firefox with File > Exit or "Firefox" button > Exit. Give Firefox some time to close and
  2. check that it finished via Windows 7 shortcut to WTM "Ctrl+Shift+Esc" in the "Processes" tab make sure that firefox.exe is no longer running -- if it is still running then terminate it by selecting the use "End Process" button or from context menu.
  3. proceed with the install