Firefox is already running but not responding - can't kill the process with Task Manager/Taskkill
Since the last update to Firefox I am getting a 'Firefox is already running but not responding error message'. This is happening on my Win10 machine - my Win7 box is not having any issues since the update.
I have followed the advice of creating new profiles, checking for locked profiles (and being unable to remove the lock?). I have completely removed Firefox from my system - uninstalled via control panel, deleted all folders in Program Files and Users etc, removed temp files and edited the registry to completely remove any Mozilla/Firefox entries. Completely clean install - as far as I can tell - but the problem re-appears as soon as Firefox is reinstalled. I've tried all this in WIn10 safe mode as well but still no joy.
The issue seems to be that there is a process running that cannot be terminated but I'm unable to kill the single remaining Firefox.exe process listed in task manager. When I try 'taskkilll /IM firefox.exe /F' from the command prompt I get an error that the process can't be killed as an instance of it does not exist. If I try 'taskkill /IM firefox.exe /T /F' it advises that a child process is keeping the main process alive - explorer.exe. Terminating explorer.exe does not free up the firefox.exe process for termination (same error of the instance not existing). The only way to clear the process is to reboot my system, Firefox will then start ok but when closed the issue will occur again.
I'm on my 4th clean install and the issue persists, so any help or advice beyond what I've tried would be appreciated.
All Replies (7)
I am also experiencing this issue on my Windows 10 laptop. I cannot kill the firefox.exe process in Task Manager nor through the Command prompt. After I uninstall Firefox and reboot my machine, the firefox.exe process is no longer displayed in Task Manager. I do a fresh install of Firefox but when I try to open it I receive the error:
Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window.
I press the Close Firefox button and it adds another firefox.exe process In Task Manager. The same error (as above) is displayed. I can end all of the firefox.exe processes except for 1. When I try to close the last process, I receive this error:
The operation could not be completed. Access is denied.
I hope there is a solution to this, I have spent a lot of time searching for it but nothing has worked :(
Sames goes with me, my Windows10 laptop which has a 64bit OS version had the same issues with this. I might try the 32bit version of firefox later on and see if it helps.
felixthadog said
I am also experiencing this issue on my Windows 10 laptop. I cannot kill the firefox.exe process in Task Manager nor through the Command prompt. After I uninstall Firefox and reboot my machine, the firefox.exe process is no longer displayed in Task Manager. I do a fresh install of Firefox but when I try to open it I receive the error: Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window. I press the Close Firefox button and it adds another firefox.exe process In Task Manager. The same error (as above) is displayed. I can end all of the firefox.exe processes except for 1. When I try to close the last process, I receive this error: The operation could not be completed. Access is denied. I hope there is a solution to this, I have spent a lot of time searching for it but nothing has worked :(
Yeah, already had spent days. Still the same so far. Might be with the firefox app itself.
I think, its with the 64bit of this firefox that encounters the said issues. So far I did install the 32bit version of firefox and as of the moment it is still okay. Will then repost once I encountered the same thing again.
Well so far I had to uninstall Malwarebytes protection to be able to get Firefox 64bit working.
Only thing I can add to the above is that that I see five firefox processes under "Details" of Task Manager. If I try to end one of the processes after getting the error message of "Firefox is already running" etc., one or two processes will disappear then regenerate. Internet Explorer here I come. :-(
Seem none of the solution resolve this problem, I have this problem too and I can't get rid of it.