(Doing so might require the assistance of Unlocker.) The location of that file would depend on whether the system was using an installed or portable version of Firefox. Geek observed that the Mozilla page offered solutions for multiple possible Firefox problems, but suggested that a common solution would be to delete the Firefox parent.lock file. The remainder of this post focuses on Firefox-specific solutions.Ī How-To Geek webpage pointed toward Mozilla’s Profile in Use webpage. Since it seemed like a generic problem, I wrote a separate post that explored possible solutions to that problem. I found that others were getting this error message for programs other than Firefox. I didn’t want to have to be restarting my computer all the time. But after doing that, the problem would soon recur. When I right-clicked > End Process (or End Process Tree), I got an error: But like others, I couldn’t kill the two that remained. That took care of one of the three firefox.exe processes. I closed the Firefox 44 session that I had just installed. It showed three firefox.exe processes, but no FirefoxPortable.exe processes. (My Run dialog was set to commence tasks with administrator privileges.) I looked in its Processes tab. I went into Windows Task Manager (available via Ctrl-Alt-Del or by using Win-R or the Start Menu to open the Run dialog > taskmgr.exe). So that was one solution to the restarting problem.īut I continued to try to make the portable version work. Unlike the portable, it was able to load. I didn’t have that installed, so I downloaded and installed it. Please close other instances of Firefox before launching Mozilla Firefox, Portable Edition.Īt this point, the most recent version of the non-portable, installed Firefox was 44. When I tried, I got this error:Īnother instance of Firefox is already running. I decided to try to kill and restart Firefox, in case that would fix the problem. Sometimes it would work to copy the URL and try again in another tab, but that wasn’t working for these tabs. The URL was there in the address bar, but the page was blank. I was using portable Firefox ESR (Extended Support Release) 38.6.1 in Windows 7.

Why does firefox open so many processes