User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; sv-SE; rv:1.8.0.1) Gecko/20060111 Firefox/1.5.0.1 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; sv-SE; rv:1.8.0.1) Gecko/20060111 Firefox/1.5.0.1 I recently upgraded firefox, when it prompted me. Then it wouldn't start, saying it was already running and suggesting me to close it down or restart the system. To fix, I had to reboot, since there was no firefox in the task manager. I also reinstalled firefox a couple of times before rebooting but that didn't help. Reproducible: Couldn't Reproduce

Maybe related to Toolkit bug 278860, bug 321786 comment 2 or bug 287667 comment 4?

(In reply to comment #1) I don't think so, those all deal with profile issues and I haven't even been asked to make/use a profile ever in Windows XP. Only on a Unix system it asks me to do that.

I also have this "bug" on windows xp professional sp2 with firefox 1.5.0.6. I tried restarting the computer, i tried to reinstall firefox and i also tried to end the process but it was not in taskmanager. i also tried ending the process whilst the message was displayed but also had no effect. the message states "Firefox is allready running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system." HTH

(In reply to comment #3) > I also have this "bug" on windows xp professional sp2 with firefox 1.5.0.6. I > tried restarting the computer, i tried to reinstall firefox and i also tried to > end the process but it was not in taskmanager. i also tried ending the process > whilst the message was displayed but also had no effect. the message states > "Firefox is allready running, but is not responding. To open a new window, you > must first close the existing Firefox process, or restart your system." > HTH I have the same message with an installation on win 2k. Removed and reinstalled, same mssg. Nothing running on task mngr. Always duplicatable. Should I see anything if I run msconfig.exe on the startup or service tab?

all you guys have to do is open task manager click on the processes tab.Search for Firefox.exe and click end process.

Reporter, do you still see this problem with the latest Firefox 2? If not, can you please close this bug as WORKSFORME. Thanks!

I am not the Reporter, but I got the same Problem with Firefox 2 and I even have tried installing Firefox 2 German Version but both with the same Problem. to #5 : If only it was so easy. There isn't any instance of Firefox running on TaskManager(Processes Tab), I tried msconfig.exe(there wasn't anything, either), rebooted my computer 10 times, reinstalled FF at least 6 times and I still got the Problem...

Sounds like you have a parent.lock file in your profile dir for some reason.

I have not had this problem since I posted, neither in 1.5 or 2.0; I'm closing as WORKSFORME.

Way to go!! You haven't got this problem anymore... But perhaps you arent the only person on this planet?? Finally I found the bug I searched 3 months for, and 2 days after I found it, you're closing it. Thanks.

Triggafingah try http://kb.mozillazine.org/Browser_will_not_start_up

Thanks to Steve England, I just found out how to completely solve the problem: (A clean reinstall won't help, either, because these files will stay!) Go to: C:\Documents and Settings\<username>\Application Data\ and delete the Mozilla folder. I heven't thought of this first, but the Folder "Application Data" is hidden. Just go Extras ---> Folder Options and there you'll find an option how to make hidden folders visible. Sorry for my last post, but I think you can imagine how I felt like after not using Firefox for 3 months ^^"