User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322) Build Identifier: After I close Firefox, I get an error message Firefox is alreadyn running but not responding. To open a new window, close existing firefox or restart computer. Task manager does not have a firefox process running, so I have to restart. Reproducible: Always Steps to Reproduce: 1.OPen firefox 2.Close firefox 3.try to open it again 4. restart computer Actual Results: I have to restart the computer to reopen the browser. Open without restarting

I am having the exact same problem. I have closed Mozilla and when I go to open the browser it tells me that the program is already running so I need to either close it or restart my computer. When I open my task manager there is no instance of Mozilla running so I have to restart my computer.

I'm having same issue. 1. I Quit Firefox (FF). 2. I click FF icon to open. 3. I get the following Dialog Box with header - "CLOSE FF"..."Firefox is already running, but is not responding. To open a new window, you must first close the existing FF process, or restart your system". I restart the system. Regards, Peter

Karen, all - version 3? Do you see this with a new, clean profile? http://kb.mozillazine.org/Profile_Manager#Creating_a_new_profile

Yes, by creating a new profile, it now works, although without my previous bookmarks, etc.

I am having the same problem. I get this message when I try to re-open Firefix: "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 have to restart computer.

I am running firefox-3.6a1pre.en-US.win32.installer.exe 07-Apr-2009 11:31 I get this problem/message ALWAYS when I start Firefox, after I just closed it. but when I wait some seconds between closing and reopening it is fine for me. When I start a 2nd session while 1st session of firefox is running, everything is fine. Why is not just a 2nd second session started, when the first "window" is closed but not all tasks totally shut, instead of the message coming up.

I have the same issue except & can't kill the process either thru Task Manager. Must restart the computer.I'm using Vista 32bit. This is an old bug.Why has it not been fixed. I'm running the latest version 3.0.10. Also pages stop loading coming up blank.No problem with my internet connection. Did not have the prolem before this last firefox update. FIX IT.

to #7 Guess You are wrong here with comments like - why has it ..... - FIX it THIS is a freeware and many work on it to improve it.

Well I'm sorry. I like using firefox & it seems this is an old bug.I've found similar topics along this vein. Other than restarting the computer deleting the parentlock file nothing else works. How do I stop this from happening? Any other suggestions appreciated.

This same issue happens on Vist Business with SP1. Firefox is my preferred browser, however, it is becoming very inconvenient to use due to this issue. I don't want to have to reboot my system (which is the only solution that consistently works for this problem) in order to browse the internet. I wind up using IE and Google Chrome more often that I really want to. This issue has been around for a while and has similar symptoms on multiple window operating systems. I and others are quickly becoming disalusioned with Firefox due to this very inconvenient error presenting so often. Isn't there anyone that has the knowledge on the development team to fix this? This is not unconfirmed, do an internet search, it is happening all too often and at least daily on my computer. I think if anyone has an interest in keeping Firefox the number 1 browser that this issue needs to be one of high priority.

few things: a) can you reproduce if firefox has been started in safe mode? b) comment 0 and comment 1 are all about firefox NOT in taskmanager, so if you do see firefox in task manager then this bug is probably not for you, but ... c) as a workaround, if firefox is in task manager, try "end process tree" rather than just "end process" (In reply to comment #6) > I am running firefox-3.6a1pre.en-US.win32.installer.exe > When I start a 2nd session while 1st session of firefox is running, everything > is fine. Why is not just a 2nd second session started, when the first "window" > is closed but not all tasks totally shut, instead of the message coming up. Bernhard, if you can reproduce using safe-mode, you should file a bug on this and post the bug# here.

a) How do I start Firefox in safe mode? Does this refer to starting the OS in safe mode? b) yes. Firefox is in the task manager; many times there are multiple instances in task manager c) 'end process tree' is no more effective than 'end process'

(In reply to comment #12) > a) How do I start Firefox in safe mode? Does this refer to starting the OS in > safe mode? two different things. FF = http://support.mozilla.com/en-US/kb/Safe+Mode > b) yes. Firefox is in the task manager; many times there are multiple instances > in task manager now that would be a rare thing. how many tasks - just two? if you haven't specified -no-remote on startup then multiple tasks is a separate issue and you should file a new bug. please cc: me. > c) 'end process tree' is no more effective than 'end process' I mentioned it only because in the 2 cases in the past 2 years where I was unable do do normal "end process", what worked for me was 'end process tree'. But I don't know why 'end process tree' worked, nor do I know under what conditions it wouldn't work.

(in Replay to bottom of #11 Bernhard) Problem of impossible fast restart is still reproducible. (2nd start works) - I used latest 3.6a1pre of today 11.5.2009 5:47 - I created a link for Minefield-Safe-Mode to realize a quick start - I opened TaskManager to watch the process - I started Minefield-Safe-Mode - I closed Minefield-Safe-Mode - I started Minefield-Safe-Mode - - first Minefield-Safe-Mode was still displayed) - - 2nd Minefield-Safe-Mode was added Now error message is displayed: FireFox s already running, but it is not responding. To open a new window, You must close ........ If I just wait a few seconds, then I can restart MineField. Problem might be my slow computer, the slow closing down of the first firefox, but I guess a wait 3-seconds loop if first process is still closing, whould help here. Please tell me what I shall further test, may be with an extra built.

spinning_30, Karen, do you still see this problem is you use the beta? http://www.mozilla.com/en-US/firefox/all-beta.html (In reply to comment #14) > (in Replay to bottom of #11 Bernhard) > > Problem of impossible fast restart is still reproducible. > (2nd start works) > ... > If I just wait a few seconds, then I can restart MineField. > > Problem might be my slow computer, the slow closing down of the first firefox, > but I guess a wait 3-seconds loop if first process is still closing, whould > help here. > > Please tell me what I shall further test, may be with an extra built. great detail. If you wait a few seconds to a few minutes and it *does* eventually shut down, then this bug may not be your issue. You probably want bug 407981, which seems well defined.

uupps, thanks, yes, I do not have to restart windows, just to wait for firefox to close before reopening works. I now continue reporting on bug #407981.

(In reply to comment #16) > I do not have to restart windows, just to wait for firefox to close before > reopening works. Does that apply to anyone who is affected by this Firefox shutdown problem? How long you have to wait until you will be able to start Firefox again? Is the process removed from the task manager immediately or is it sill hanging around until Firefox has been completely closed? Please watch in parallel.

Same problem using Vista Home Premium/ADSL2+ Site being accessed using FF freezes Turn off FF Restart FF Get subject error message Cannot restart via Start button>Restart (does not work) Cannot cancel FF through Start Task Manager Press restart button on PC tower (wait eternity while PC closes and restarts) Restart FF

I'm having this problem just since I upgraded to the lastest version of Firefox a few days ago. (Version 3.0.10). So far it only happens when I click on a link in my email (Windows live mail). I have to go to the task manager, but it doesn't show up in the applications tab, so I go to the processes tab, and end it from there by choosing firefox.exe. This is a real pain in the neck because I can't click on any links in my email. I hope there is a fix very soon. If not, can anyone tell me how to go back to the previous version of firefox that I had before I upgraded. Thanks.

Kathleen, can you please check if Firefox is the default browser? Open the preferences and change into the advanced pane. Does it solve the problem when clicking the make default button? If not, the dialog is always shown while Firefox is running and you are clicking on a link inside an email? Samuel, are you aware of a change in that area for 3.0.10?

Thanks Henrik Hi, yes it is the default browser. If I have firefox open, the links seem to work. If I close it, and then click on an email link, that's when it doesn't work and I get the error message. It's as if the browser doesn't completely close or something because the error says its running and it shows up as a process (but not running program). It is quite annoying. Kathleen (In reply to comment #20) > Kathleen, can you please check if Firefox is the default browser? Open the > preferences and change into the advanced pane. Does it solve the problem when > clicking the make default button? If not, the dialog is always shown while > Firefox is running and you are clicking on a link inside an email? > > Samuel, are you aware of a change in that area for 3.0.10?

(In reply to comment #21) > Hi, yes it is the default browser. If I have firefox open, the links seem to > work. If I close it, and then click on an email link, that's when it doesn't > work and I get the error message. It's as if the browser doesn't completely > close or something because the error says its running and it shows up as a > process (but not running program). It is quite annoying. That sounds like you are affected by bug 407981 as well. It would be nice when you could add a comment to the mentioned bug and your observations how long it takes until the process is removed from the task manager. Further it would be nice to know if that happens all the time.

This should be a valid report. So confirming for now and adding dependency to bug 407981 which is one factor to raise this problem (probably the most common one).

(In reply to comment #20) > Samuel, are you aware of a change in that area for 3.0.10? No, but this is also an older bug as filed. I'm not sure why people have to restart their entire OS, but most of the comments in this bug refer to bug 407981 not to a new issue. Having to restart the OS is a different bug.

hello im having the same problem but mine will first the browser with hang ie: it will stop but it will still be open, the page will no longer refresh or load. then when i close it it will give the this browser needs to be closed before you can open it msg then when you tree to end the task it wont end either by reg or by using end tree. only way to use browser again is by restarting vista. also cant start it in safe mode once it hangs. i have not found any way to fix this as of yet i have searched with google

Hello, I just updated my Firefox to version 3.5.5 and now it no longer wants to start. I get the same message as everyone else, restarting the pc does not help and the firefox process is not in the processlist either. Creating a new profile did allow me te start Firefox again, but without my bookmarks and no access to my saved passwords, wich is even worse for me than not having access to my bookmarks... Is there a way to retrieve those passwords?

Please check if your old profile is accessible on disk no folder/file permissions have been screwed up. Further if there is a parent.lock file in the profile folder please delete it. Can you remember what you have done before closing Firefox to apply the update? So it has never started after the update?

ok i had this problem once apon a time and i found out that if you had zone alarm installed on your computer it causes programs to hang not just mozzilla. i changed to online armor (another free one) and it solved the issue. hope this helps.

Seems this problem started when Foxfire was updated to Version 3.5.7 on 1/6/10. It is very annoying and really do not care to restart my OS so often. Hope we can find resolution soon.

I am having the exact same problem. I have closed Mozilla and when I go to open the browser it tells me that the program is already running so I need to either close it or restart my computer. When I open my task manager there is no instance of Mozilla running so I have to restart my computer. Does anyone have a fix for it?

There is a workaround: remove the lock files in your profile folder. This is a workaround. This is not a solution. This needs to be fixed.

The problem seems to be that Firefox takes too long to shut down. So when trying to open another instance, the old instance is still running. Currently Firefox just displays this dialogue and gives up. This leads to data loss if I've tried to open a web page from another program: Firefox discards that page's address. There should be a way to reissue the command that started Firefox, for example a Retry button on the dialogue. Ideally Firefox would retry the command automatically every few seconds, and close the dialogue once Firefox starts properly. The dialogue would then become essentially a splash screen, with words to the effect of "Firefox will start shortly; if it doesn't you may need to restart".

I have been having this very same problem. Even though I delete the parent.lock file before restarting the software after a clean re-boot it never is a permanent fix. Please... this needs to be fixed. It's been going on for nearly three years!

I have the same issue and it is so annoying. It is to the point where I might switch to Chrome. I can go to the task manager in Windows 7 and end the processes, but it wastes time and at this stage of firefox, this should not even be an issue. I would say it is one of the more persistent bugs that needs to be fixed ASAP.

I also have got this problem. When I upgrade my firefox browser from version 8 to, either 9 or 10 or 11, I have problems of not able to open firefox instance after working with firefox for sometime. Once I close a running browser and attempts to open a new one, it simply doesnt start. If I go to Task manager, one instance of firefox.exe will be running. I tried closing all instances and restart but still it won't work. I noted that this problem was not there with firefox 8. This is only with 9, 10 and 11. Waiting for fixes to solve this issue.

This issue can be reproduced with Windows 7, Firefox version of 12.0 . Just open FF and close all the windows. Most of the time firefox.exe remains listed in task manager, so it was not really quited as would be expected by closing all the windows. After that lauching FF with it's start icon is impossible until the exe has been manually killed out from the task list.

Windows XP SP3 Firefox 12. Only way to re-open Firefox is to close the existing Firefox process or restart the system. If this is not corrected (I tried a System Restore, but this didn't solve the problem), I will have to switch to another browser.

I am having the same issue with Firefox 14.0.1 on Windows 7. Thunderbird is occasionally behaving the same. Annoying workaround is killing process in Task Manager.

(In reply to blaz.luin from comment #39) > I am having the same issue with Firefox 14.0.1 on Windows 7. Thunderbird is > occasionally behaving the same. > Annoying workaround is killing process in Task Manager. There is no need to restart your system when you receive an error message as "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.". Just what you need to do is: 1. Go to start 2. Enter services in search 3. Go into services. Here you will have all the applications installed on your system. 4. Search for mozilla firefox/ thunderbird 5. If the service reports as started, then stop it and start the service again 6. You will not get the problem now. this method can be used for any of the process that reports the error as cannot be started as the instance is already running.

Have tried all the above and many other proposals found in forums. Firefox is running and needs to close,( but opens after a few minutes ) firefox not responding, firefox hangs a lot surely this problem should have been resolved by now ??? if I download an earlier FF, will this help ? What's the logo.... Next generation !!!! LOL

After few seconds once the Firefox is closed, this message wont be displayed and the FF will start normally.. Additionally, you can kill the task in Task manager..

(In reply to Karen Wondergem from comment #0) > User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET > CLR 1.1.4322) > Build Identifier: > > After I close Firefox, I get an error message Firefox is alreadyn running > but not responding. To open a new window, close existing firefox or restart > computer. Task manager does not have a firefox process running, so I have to > restart. > > Reproducible: Always > > Steps to Reproduce: > 1.OPen firefox > 2.Close firefox > 3.try to open it again > 4. restart computer > Actual Results: > I have to restart the computer to reopen the browser. > > > Open without restarting I have a similar problem. every time I close firefox it's still running on the background. Altough I can see firefox in the task manager (in the proccesses tab), I still have to click on "finish this task" in order to reopen firefox. that's pretty frustrating...

Since "a recent nightly build" (now on 30.0a1 (2014-02-10)), I have been getting this problem regularly. Using File->Exit appears to be the safer way to quit - Ctrl-W on the last open tab/window usually leaves the firefox process running. Platform: Windows 8 First seen: Nightly 29.something Reproducible: Yes (though can be intermittent) As noted above, there was definitely a degradation introduced in Nightly 29.x shortly before Nightly moved to 30.x but unfortunately I didn't think to note the exact date (as ever, putting it down to a minor glitch likely to be fixed quickly).

To follow up on my earlier comment, the problem with the recent nightlies appears fixed (within the last three or four days). Current build 30.0a1 (2014-02-14) is not showing the problem.

Maybe I spoke too soon. 30.0a1 (2014-02-15) has the problem. I'll not report again until I've done more extensive tests.

One would think that after so many years the geeks who know how all of this works might have figured it out. Apparently not. I have the latest Firefox (29.0), windows 7, 64 bit machine, Home Premium. Lately when I try to close my browser down and then reopen a minute late I get a message saying that Firefox is still running. Well it isn't. When I check Task Manager IT IS NOT LISTED so I know it is not running. The only way I can open the browser at this stage is to reboot the computer. Seriously, is this what is considered 'normal' or am I just uninformed. I have been battling with Firefox issues for a few years now and there seems to be one issue after another. SO I THERE A FIX OUT THERE OR NOT? OR DO I HAVE TO DO THE UNTHINKABLE......GO BACK TO THE BROWSER I ABANDONED A DECADE AGO (IE)?

Well, the problem that this bug is not fixed yet is that there are many factors, which could cause that behavior. Personally I never have seen this issue on all of my systems. So what we need is help from those people who are affected, so we can nail down the problem. Given that you are frustrated, and want to get rid of the problem, would you mind to help us out here? I would appreciate that. So here some questions: 1. What are your system details and which version of Firefox are you using? 2. How often does it happen, and are you able to replicate the behavior constantly? 3. Does it also happen when you run Firefox in Safe Mode with all add-ons disabled? See https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode 4. Do you see the same with a fresh Firefox profile? See https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles 5. If it doesn't appear in Safe Mode or a fresh profile, please try to disable add-ons. A single one or a combination of different ones might cause the problem Please report back your findings. Thanks.

(In reply to coachop94 from comment #9) > Well I'm sorry. I like using firefox & it seems this is an old bug.I've > found similar topics along this vein. Other than restarting the computer > deleting the parentlock file nothing else works. How do I stop this from > happening? Any other suggestions appreciated. I agree. I got an 'in your face' response when I said much the same. This is an old problem so the developers should not be offended if the Indians are not happy. I mean how much personal effort does one have to go through to fix something which the geeks would be able to fix if they wanted to.

Having same problem once I went onto V29 running on windows7 64bit. This is happening nearly all the time, was a big fan of firefox but with recent slowdowns and now this makes me want to go back to explorer or chrome. Maybe this is what Mozilla wants. Thought this was a new problem but just looked at the first time posted and wow cant believe this is still going on, thought it was the new V29.

(In reply to jsgtts from comment #51) > Having same problem once I went onto V29 running on windows7 64bit. This is > happening nearly all the time, was a big fan of firefox but with recent > slowdowns and now this makes me want to go back to explorer or chrome. Maybe > this is what Mozilla wants. Thought this was a new problem but just looked > at the first time posted and wow cant believe this is still going on, > thought it was the new V29. My problem seems to be intermittent. You might try updating all of your drivers and see if this helps. I did (using Drivermax) and Firefox is currently working. But I am not holding my breath as Firefox seems to have become problematic over the years and IE has improved to the stage where a decision will soon be made.

There is a fix in Firefox 29.0.1 for one of the reasons for slowdowns on exit. See bug 1005958. But there are still two known issues with the new release as reported as bug 966469 and bug 985655. It's getting worked hard on both to get them fixed.

Found out my problem, I deleted all the profiles and placed the folder OLD FIREFOX DATA folder(on my desktop)in the bin and started a fresh from new, and added all my bookmarks and login/passwords from I.E, now working fine with no issues.

I have not had an issue since I went right through all my drivers and updated. But this does not mean that this was the problem and too early to be sure.

thought I had solved the problem but still getting the same old ****.

I have updated all of my drivers. No change. I am reluctant to delete profiles or reset Firefox as I am concerned that all of my many bookmarks may be wiped. This would be a disaster. If anybody has a bullet proof way of doing this then I would be happy to find the way out of this decaying browser which used to be state of the art but which now looks like it could be dying a slow death. As much as I hang on I am beginning to use IE which now appears to be trouble free and which is a true 64 bit browser unlike the Firefox (still) 32 bit dinosaur. We live in hope!!

It's not that hard really. If you click on "Show All Bookmarks" you'll see there are options to export, import and back up your bookmarks. Also you can easily create a new profile while still keeping the old one using the profile manager. So if something goes wrong or you forgot something (like extensions or passwords) you can go back to your old profile. There are probably some extensions which could make this even easier, like Profilist which allows you to create and switch between profiles from the app menu. https://addons.mozilla.org/en-US/firefox/addon/profilist/ You could also use firefox sync (though personally i don't recommend it - it's **** in my opinion). There should be plenty of tutorials on the net.

Thanks annaeus. I exported bookmarks to my desktop and to make sure it worked I imported them into IE. Worked fine. My only complaint was that I now added new bookmarks on top of some which are already there so I have a duplication and a bit of a mish mash. I can sort this out though. I downloaded profilist and then found it in FF extensions. Finding this in the menu was challenging but got it.

The new profile seems to be created but with no extensions and no add ons. Is there an easy way to transfer these across as it would take many hours to manually do this.

No, the point of the reset is to return to a clean slate (and trying to import – not copying! – some user data like bookmarks back from the old profile). I'd suggest that you only install the addons you absolutely need and see if this works better. If not, the source of your problem may be one of your essential addons. Disable them one by one (restart for the addons that require it) and see if the problem goes away: Then you have the culprit. Better yet: Use the clean profile, and add an addon or two back per day, and see if the issue returns.

After many years of using Firefox I have finally been forced to give up and (reluctantly) go back to IE. This is one of many bugs which seems to have crept into the browser. The reasons I have given up is firstly the Abode Flash is still a problem after a decade (sends my computer into overdrive) and secondly the browser is still a 32 bit dinosaur. Loyalty only extends so far. Extinction ensues.

Back to IE, rambotrader? lol. That's like saying "I give up on internet". Anyway, I'm having this issue in FF Developer addition. Same as above - I'll close FF, and when I try to open it again it tells me there is already a FF open. And there isn't. On OSX Yosemite. Can't Force Close - it doesn't show up as a running process there.