How to fix the Mozilla Firefox web browser if it will not start

Posted on in Categories Linux, Linux desktop, Mozilla, RedHat/Fedora Linux, Suse Linux, Troubleshooting, Ubuntu Linux last updated February 7, 2007

This may sound a little weird but sometime Mozilla Firefox will not start. You click on Firefox icon and nothing happens. So how do you fix the Mozilla web browser if it will not start?

This may happen due to two following reasons:

a) Mozilla Firefox may be running and it is not responding at all

b) ~/.mozilla directory is corrupted while updating or installing an extension

Mozilla Firefox may be running and it is not responding at all

First see if Firefox is running or not by typing following command:
$ ps aux | grep firefox
Ouput:

vivek     3174 19.5 13.9 209040 107008 ?     S    20:17   7:30 /opt/firefox/firefox-bin

If a process is running, kill it by typing:
$ kill 3174
OR
$ killall firefox-bin

Now try to start Firefox

~/.mozilla/firefox directory is corrupted while updating or installing an extension

Just rename a ~/.mozilla/firefox directory
$ mv ~/.mozilla/firefox ~/.mozilla/firefox.old

Now try to start Firefox.

Please note that you can apply above procedure to other Mozilla products such as Mozilla Browser and email client.

109 comment

  1. Good tip on Firefox, and the other Mozilla family products. I have found this to be true in Netscape prior the arrival of Firefox or even Mozilla’s browser.

    I wish there was a way to permanently fix this problem, either in their code, or in a start up script that kills it and starts a new one.

    1. You can always try ALT+DEL to open the task bar.

      If firefox is running as indicated in the “Processses” section, end the process, close the Task Manager and re-open your firefox browser. This is a easier approach.

      1. am trying to remove firefox compeletly and reinstall it it keep saying that it is open but am not seeing anything on the screen opening it is a prolem i need help

      2. Sam’s suggested fix was right on the money. Firefox now up and running — in less than 2-3 minutes. FYI, the problem began when Firefox attempted to install an update and just disappeared.

  2. absolutely useless. Where does one type $ ps aux | grep firefox ? I have uninstalled and installed Mozilla Firefox several times. It did work sometime ago but no longer works. Have given up. Thankful there are browsers that work – fire fox doesn’t.

  3. I’m with Geri! I have windows xp and firefox wont start. I double click and get an hour glass and then nothing. I’m sure it is starting because I see it in windows task manager. The scary thing is that it is constantly starting and stoping and re-opening but ultimatly I never get the browser open. I have run anti-virus software and removed things but nothing has fixed this. Firefox is a valuable program to me because I run dreamweaver and always have lots of browser tabs open.

  4. Hello,
    Really your site is very interesting,it gives my knowledge about many things.
    I am a beginner with Linux and i knew a bit of Unix.
    Can you guide me to get good information about linux kernel and filesystem.
    In my machine i have one problem also. I have fedora 7 in my machine,now a days it is becoming very slow.
    When i am checking top then it is displaying nautilus using 102% of cpu,how come it is possible?
    Please solve my problem, i will be highly great full to you people.
    Thanks and regards,
    Shaili Vaish

  5. Thanks for the tip.
    I found a problem after installing Omnipage SE4 that came with a Canon printer. It tried to hook into Firefox. So I uninstalled it, then Firefox would not start.
    I’m using Windows XP so looked in Task Manager – sure enough firefox.exe was running. After killing the process all is well.

  6. HALOOOOOOOO!!!!

    I’ve added some add-ons which were flash pad or something and mozilla skins, then i got my mozill freezed and it didnt respond! I’ve uninstalled and installed several times but it couldn’t help me out of this trouble. I’ve also deleted what in the plugins folder were(in mozilla folder, program file).

    But once more time, it didnt give me any diffrences!

    I think this tutorial would work, but i dont know exactly where i should put those codes on.

    Can anyone tell me how?

    Thank u so much,
    Gretta

  7. ADDITIONAL INFORMATION:

    Vivek’s instructions in this post are for Linux machines only. They will definitely not apply to Windows users, and I’m doubtful if the second one even applies to Mac users.

    For Linux and Mac, the command “ps aux | grep firefox” must be typed in the Terminal.

    I have a Mac and I don’t see the ~/.mozilla/firefox directory at all.

  8. same things to say as Geri and Andy.
    can someone help with windows XP.

    FF3 starts(AS i can see it in task manager) and then nothing happens.

  9. ive got windows xp and recently my firefox just wont start ive looked and followed alot of advise but nothing seems to be working.when i bring up task manager it says its running but cant get a browser open.I havnt recieved any message at all about there being an error like alot of the problems on this page. i am completely baffled can any one help me im lost without it

  10. Try killing running process. Select process > Right click > Select kill. Make sure your system is free of virus and other nasty stuff. Also, use latest version of Firefox i.e. FF3.1

  11. Hi!! guys!!! we have a very same prob!!!my firefox is not starting….i think its a virus infection…
    But i have the solution…if u have the same prob as mine….

    It works for me but i can’t guarantee if it will work for u. but at least, i just want to help….

    I try to uninstall firefox but it simply can’t. it is because of malware or spy ware. so clean up your pc first. I like avg but their 8.0 make my comp slow so I try AVIRA.try to kill the process of firefox if it is still running…check ur task manager…..

    After Cleaning your pc…
    If you cant uninstall firefox. Just delete its directoties in the Program files folder.
    Also delete the shortcuts in your desktop or quick launch.

    Then download the latest version of Firefox….

    Install it……And used again!!!! Gud luck!!!!

    Tell me if it works!!!! [email protected]

  12. My firefox dosent work also , infact this the third time its stopped working after formatting the hardrive, ive tried everything, nothing works…shame really i really loved firefox & dont trust IE.

  13. For windows guys, the users firefox home directory is in “C:\Documents and Settings\your_log_in_name\Application Data\Mozilla\”. So either rename this folder or remove it. This issue is due to your some corruption is the firefox settings.

    Note that removing or renaming will remove all the saved data in your browser on both Linux or Windows.

  14. All platforms browse to the firefox install directory
    type firefox.exe –profilemanager (for windows) or firefox –profilemanager (for linux)
    delete default profile
    create new profile and start firefox

  15. My firefox (3.05) did not start either and had tried everything. What worked for me was to copy the mozilla folder from application data from another computer that mozilla worked fine, and paste them to my computer.

  16. Can’t open firefox, click on the icon and nothing happens. I have scanned for viruses, reboot, restored to different dates, uninstalled, but wouldn’t at first, stating close firefox, still no luck. If I log into quest on win xp it works fine, but will not open for me. Worked on this most of the day…any suggestions. Thanks.

  17. I am running 2000 at the moment, about to switch to xp. I started using Opera when I lost Firefox and I like it a lot. I loved my firefox though, I have recently installed Ubuntu and have the same prob with firefox there too. I am very new to the Linux experience but I can see that when I finally learn it it will be a great thing.

  18. I’m having the same trouble as a lot of you do. When I try to open my firefox, the result is that it won’t open. I’m thinking that it was when I tried updating it, it got corrupted by something. Does anyone know how to fix this? If you do, please post it up here. Thanks!

  19. just installed win7. after a few days of honeymoon, i now have a process that constantly starts and stops. the process shows as whatever is my default browser (i uninstalled FF and the same issue occurred, now with IE as the process.) Process cannot be ended by right-click “end process.”

    Ideas?

  20. Hi. My forefox was not opening after updating it.I have Vista. I got it to finally work again by:
    -Go to your computer icon and click on you “C” drive.
    -It will then show a list of your progarams. Make sure you click on Program files. Since I have 2 program files listed, I had to click on the one that said Program Files(x86). This one contained Firefox.
    -Out of the list, right click on the Firefox program and select delete.
    -Once you are done, then delete it from your recycle bin.
    When you are finished, go on your browser that works, go to Mozilla and downlod
    Firefox.
    -When I did this my Firefox was back in business.

    1. You are the best! Worked for me perfectly. Although, I had to scroll down and read Sonny’s post (Sonny May 25, 2010 Since I’ve updated Vista Firefox all of a sudden doesn’t work anymore. Deleted it from the C drive (program files) and then deleted it from the bin (Like Cathy said Feb 23). Downloaded an older version from Firefox (3.5.5) and it works fine.) You Both ROCK!

  21. Same. Updated to 3.6 and everything seemed fine. Once the update ran, I relaunched and it was all good. Sat down later that evening, bam, no Firefox. Have tried all ideas listed here. Vista machine. Unable to open profile manager. Launches on taskbar and processes list, but does not open on screen.
    Near giving up. I really hate to go back to IE full time, but if there’s no fix to this, I can’t keep banging my head into a wall.
    Have any fresh ideas on how to fix this since the new 3.6 push, I’m all ears.

    1. Hey if ur having problem opening the profile manager, go to the start menu if using windowsxp and type the following: “C:\Program Files\Mozilla Firefox\firefox.exe” -ProfileManager should get a file that can be opened to give access to the profile manager. other problems use the mozilla si

  22. your own fault for opening a keygen. Best help I can offer you – get rid of it, scan for viruses, spyware, bots, etc. You’ve likely just infected yourself. Fubar.

  23. Since I’ve updated Vista Firefox all of a sudden doesn’t work anymore. Deleted it from the C drive (program files) and then deleted it from the bin (Like Cathy said Feb 23).
    Downloaded an older version from Firefox (3.5.5) and it works fine.

  24. Help! Can someone please help!

    I am running XP and Firefox is refusing to open.

    I have read instructions/advice from forum but don’t understand the lingo

  25. type this WHERE?? First see if Firefox is running or not by typing following command:
    $ ps aux | grep firefox
    Ouput:

    vivek 3174 19.5 13.9 209040 107008 ? S 20:17 7:30 /opt/firefox/firefox-binIf a process is running, kill it by typing:
    $ kill 3174
    OR
    $ killall firefox-bin

  26. “mv ~/.mozilla/firefox ~/.mozilla/firefox.old”

    ah man i been messing with my firefox and it wouldnt work anymore!! thanks for saving me from confusion!!

  27. Hi
    My firefox is doing the timer for a few seconds and nothing else.
    I have tried uninstalling and reinstalling, remnameing the firefox.exe file to firefox2.exe, Still nothing.
    When i check task manager running processes its not there either.
    Am at a loss on what else to do. I have windows xp if anyone knows what I can do please help!!

  28. same problem,i am using Xp, unable to open the mozilla firefox
    even unable to view the task manager for checking that mozilla program is running or not.what might the problem.Any one can suggest how to enable the task manager and firefox browser.after several times uninstalling and re installing the same problem no improvement.

  29. heyy i have the same problem as everyone else on here…just today i was on my firefox. i closed it, turned off my comp and when i came back on, it wouldnt even open. i cant open anything thats related to firefox…not even the profile manager or even safe mode. i have uninstalled it and reinstalled it many times and i’ve even scanned my computer for any viruses or anything of that sort. NOTHING! i’ve tried looking for help on different websites and this is the only one that is even similar to what i’m trying to figure out. so please if anyone can help me, i’d greatly appreciate it!

    1. Uninstall firefox.
      Go to program files and remove the firefox directory.
      Reinstall firefox.
      Choose the type of setup to “Custom” and change the default directory to d:\\program files…. or e:\\program files… [ Not in the c: ]. Complete the installation process. Go to Start menu and open the browser in Safe mode. Disable “Add-ons” and continue.
      It woks for me.
      Re enable necessary Add-ons later

  30. I just got a new laptop, that runs windows 7. my hubby installed firefox for me, and it worked great for about three or four days. then it all of sudden, when i opened firefox, it kept saying unable to connect. i know the internet is working fine, becuase explorer works fine, so it’s just firefox having the issues. however, the same time firefox quit working the laptop, did some updates to it. i’m not sure if these updates had messed up the firefox or not. anyhow, if you have soulations that would be great, thank you.

  31. Uninstall fire fox.
    Go to Program files and delete the existing Mozila firefox directory.
    Reinstall fire fox.
    Choose “Custom” While Setup and change the default directory path.
    [ do not install in c://program files ] Change the directory path into d:\\program files… or e:\\program files… also choose “Accessories” in the next step and complete the installation process.
    Go to Start menu, Accessories and open firefox in Safe mode. A window opens, disable “Add-ons” and Personal settings, continue….
    It works fine for me.
    You can re enable your necessary Add-on features later from “Tools”
    “Some Add-on may crashes Firefox”

  32. ok. i tried every f’ing windows solution on here. i have windows vista. tried removing, reinstalling, deleting directory….everything. was about to give up then i went to start menu. clicked on the mozilla firefox (safe mode) under the program files directory of start menu. it opened the window. i clicked on “disable all add-ons” and clicked continue and start. not the one that says continue in safe mode, just continue and start or whatever and it opened right up. it said while this is embarrassing….cant reload last session but then i just clicked start new session and it works fine. there you go :)

  33. i have the same problem “firefox already running, but not responding” etc.
    I can’t get on the internet at all.
    I have a linux “limpus” acer laptop – Netbook
    So far iv tried a couple of things from internet advice (on my home pc) least i can get online if i need to ..
    Any advice would be appreciated.
    Thanks

    1. Mostly this problem due to Add-ons.
      1. You can open firefox in safe mode.
      2. Then Disable all Add-ons.
      3. Go to ‘Start’, ‘All programs’, open firefox normally.
      4. ‘Enable’ Add-ons one by one and restart firefox every time.
      5. Now you can find out which Add-on crashes firefox browser.
      6. Permanently disable the Add-ons which creates problem.
      That’s all

  34. Thanks very much, i couldn’t open the browser at all before. i followed these instructions and ta-da! it works now! yay! p.s. i have no idea about computers so they must be great instructions :)

  35. Could not initialize the application’s security component. The most likely cause is problems with files in your application’s profile directory. Please check that this directory has no read/write restrictions and your hard disk is not full or close to full. It is recommended that you exit the application and fix the problem. If you continue to use this session, you might see incorrect application behaviour when accessing security features. that was the alert on my mozilla and if i type name of website its wont to open the web..

  36. I have same problems with ff 4. tried to remove program. box says firefox must be closed before continuation. click on ok but the box just keeps repeating same thing. nothing happens. tried above “solutions”but computer soesn’t recognise commands. cant uninstall or reinstall, wont start – its infuriating Now Ijust want my bookmarks saved so I can use some other browser – but still cant remove Mozilla from my computer????? I wasted a whole afternoon trying to sort this – not happy

  37. I have a vista and the firefox won’t open, instead, an “open with” comes out as if the firefox is some kid of invalid file. Help?

  38. Hello. Well my problem is one that a lot of people here have to. My father and mother were usig the computer and when I tried to use it afterwards, mozilla will not start. It’s not like when it usually happens when it just says: “mozilla is running but not responding”. It just, won’t turn on. But now, the problem is that when I click on it it says that it had a problem and crashed but when I click on restart firefox, it does not restart! Can someone please help me?

    1. Mostly this problem due to Add-ons.
      1. You can open firefox in safe mode.
      2. Then Disable all Add-ons.
      3. Go to ‘Start’, ‘All programs’, open firefox normally.
      4. ‘Enable’ Add-ons one by one and restart firefox every time.
      5. Now you can find out which Add-on crashes firefox browser.
      6. Permanently disable the Add-ons which creates problem.

      1. well, my problem is , i am unable to open any browser…..(firefox , IE, chrome)..i kept on reinstalling firefox , but nothing has happened.when i double click firefox nothing is happening.i cant even find it in task manager..(in process also)…i even tried to open in safe mode but no use.it is not showing any window with “Add-ons “.i have tried everything…changing its path and deleting its files, everything….but it is of no use….i have downloaded firefox from my laptop to PC..but no luck…pls someone help me with this..

  39. All of a sudden Mozilla Firefox stops, Not responding, very slow. scroll bar keeps showing the circle or timer icon, very irritating. Granddaughter installed Bandoos after this has been terrible has this caused the problem.

  40. you said that if ur firefox is not responding then type $ ps aux grep firefox n know its running or not.. but where should i type this commad? will you tell me pllzzzzz????

  41. renaming a ~/.mozilla/firefox directory did the trick for me after countless wasted hours.
    I suspect some add-on was to blame.
    Many thanks

  42. this worked for me:
    open Start Task Manager
    then select the tab “Processes”
    look for firefox.exe
    right click and select ‘end process’
    try launching firefox browser
    hope this helps!

  43. am trying to remove firefox compeletly and reinstall it it keep saying that it is open but am not seeing anything on the screen opening it is a prolem i need help

    1. “Ctrl+Alt+Del” to open Task Manager and ‘end process’ firefox.
      Now open firefox in safe mode and disable all Add-ons.
      Hope this helps.

  44. I’ve tried
    1.“Ctrl+Alt+Del” to open Task Manager and 2.‘end process’ firefox., but 3.Now open firefox in safe mode and disable all Add-ons where should I open it in safe mode?I’ve tried reinstalling mozilla firefox, clicking the icon but nothing is working…

  45. my firefox is not running… when i try to open it their appears.. “The exception unknown software exception (0xc0000417) occurred in the application at location 0x78b2ae6e” ..what can i do..????

  46. my firefox is not running… when i try to open it their appears.. “The exception unknown software exception (0xc0000417) occurred in the application at location 0x78b2ae6e” ..what can i do..????

  47. I am running Mozilla Firefox 18.0.1 (x86 en-US) on Windows 7 Ultimate. It was working fine a couple of weeks ago. Now when I click on icon the hour glass comes for a fraction of second….
    In task manager under it firefox.exe appears for a fraction of second and then elopes.

    Please help how I can fix this problem without re-installing it.
    Thanks in advance for your help.

    1. I had the same problem.But when i changed the compatibility mode of firefox to window xp service pack 3 ,it started working fine.

  48. Amazing!!! The solution provided here still works in September 2015. I had a completely blank window in my firefox running in ubuntu 14.04 (xubuntu + edubuntu) after an update of firefox. Even after updating firefox again two times the problem persisted until I found this page. Thank very much.

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