Sounds like it is hanging when you exit and later try to restart Firefox.

• How to stop the running Firefox process
  • In Task Manager, does firefox.exe show in the Processes tab?
  • See: http://kb.mozillazine.org/Kill_application
• What may cause Firefox to hang at exit
  • http://support.mozilla.com/en-US/kb/Firefox+hangs
  • http://kb.mozillazine.org/Firefox_hangs
  • https://support.mozilla.com/en-US/kb/Firefox+is+already+running+but+is+not+responding
• You may need to try Firefox Safe Mode
  • You may need to use Safe Mode to locate the problem: http://support.mozilla.com/en-US/kb/Safe+Mode
  • Firefox Safe Mode is a diagnostic mode that disables Extensions and some other features of Firefox. If you are using a theme, switch to the DEFAULT theme: Tools > Add-ons > Themes before starting Safe Mode. When entering Safe Mode, do not check any items on the entry window, just click "Continue in Safe Mode". Test to see if the problem you are experiencing is corrected.
  • If the problem does not occur in Safe-mode then disable all of your Extensions and Plug-ins and then try to find which is causing it by enabling one at a time until the problem reappears. You MUST close and restart Firefox after EACH change via File > Restart Firefox (on Mac: Firefox > Quit). You can use "Disable all add-ons" on the Safe mode start window.
  • See the following for more information
    • http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes
    • http://support.mozilla.com/en-US/kb/Troubleshooting+plugins
    • http://support.mozilla.com/en-US/kb/Basic+Troubleshooting

You need to update your plugins. It is important to keep them updated due to continuing security fixes and improvements in those plug-ins:

• Shockwave Flash 10.1 r82 (security update just released 2010-09-20, http://www.adobe.com/support/security/ )

1. Check your plugin versions: http://www.mozilla.com/en-US/plugincheck/
   • Note: plugin check page does not have information on all plugin versions
2. Update Shockwave Flash
   • Use Firefox to Download and SAVE to your hard drive from one of the the links below; the links take you directly to the download and you avoid the "getplus" download manager and "extras" (i.e., toolbars, virus scan links, etc.) on the main Adobe page.
   • SAVE to your Desktop so you can find it
   • After download completes, close Firefox
   • Click on the file you just downloaded and install
     • Note: Vista and Win7 users may need to right-click the installer downloaded and choose "Run as Administrator"
     • Note: Most browsers other than IE will also get updated with this one download
     • Note: To update IE, same procedure but use IE to go: http://fpdownload.macromedia.com/get/flashplayer/current/install_flash_player_ax.exe
   • After installation, restart Firefox and check your version again.
   • Download links and other information:
     • https://support.mozilla.com/en-US/kb/Managing+the+Flash+plugin#Updating_Flash
     • or you can download, save, then run the manual installers for IE, then for Firefox (and all other browsers) from here: http://kb2.adobe.com/cps/191/tn_19166.html#main_ManualInstaller
   • Also see: http://support.mozilla.com/en-US/kb/Installing+the+Flash+plugin
   • Also see (if needed): http://kb2.adobe.com/cps/191/tn_19166.html#main_Uninstall

It doesn't shut down cleanly. It's _NOT_ hanging. There's a difference.

You shouldn't take article titles that strictly. You can't include everything in a title. Hanging means that the Firefox process doesn't end completely and that the process is still active and visible in the Task Manager on the processes tab.

You can try to disable the Windows Presentation Foundation plug-in (Tools > Add-ons > Plugins). If you have the Java Console and the Java Quick Starter extensions (Tools > Add-ons > Extensions) then you can try to disable those as well.

See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems

Thanks, but this simply screams "bad design". I shouldn't have to disable plug-ins or java every time I shut down Firefox. That is just a non-starter.

The only way you are going to determine what is causing that problem is to do a little troubleshooting, by trying the probable solutions offered in this forum. The suggestion that cor-el made was to disable those plugins and see which one is causing that "hang"; do them one at a time to help figure out which is causing that problem. Also, Firefox needs a restart for disabling some extensions, so waiting to disable them immediately before closing Firefox may not work.

How is it a "bad design" if you install a plugin that doesn't work properly with Firefox and that plugin causes the Firefox to hang and not close completely?

"If you have time to whine and complain about something then you have the time to do something about it." - Anthony J. D'Angelo

It strikes me as pure laziness to keep offering this same mickey-mouse solution to a chronic Firefox problem. Java, for example, is an integral part of Firefox and FF should be properly engineered and checked to see it's not choking on Java (or any other process). To say that I can always run FF without Java if my FF isn't working properly is simply laziness. If Task Manager can shut down FF, then FF can implement a similar, efficient shut-down. It's a bad design issue, not an end user issue. And worse, it's a design issue that's been bugging FF users for years because FF support keeps offering this same bogus remedy: "Uninstall all your plugins and try again." It's time to come up with something different.

None of us here at Mozilla Support are developers, we're all users like you, who volunteer our time to help other Firefox users. We can't fix Java and we can't fix Firefox, but at least with Mozilla we have a voice with the developers via Bugzilla.

Java is not an integral part of Firefox, it is a plugin made by a different company. The Java extensions that cor-el mentioned aren't even necessary for Java to work in Firefox; the Quick Starter is just that, it opens Java a little faster when it is called for - but IMO it is flawed and causes problems for some users. The Java Console extension is really only useful for people who need to troubleshoot Java problems, AFAIK. IMO, that extension doesn't belong in the Java Runtime Environment (as it used to be called), it belongs in a "developer package" instead.

I also was having this problem and after searching for a week I came across a posting that recommended downloading SUPERANTISPYWARE, it is a free download and as strange as it seems this WORKED!! I could not get FireFox or Google Chrome to end no matter what I tried, I could not even use the Task Manager to close them and when I tired of waiting and tried to shutdown the computer it would hang waiting for the programs to allow a shutdown and I would finally give up and shut of the power,

NO MORE!!!

I hope this works for others also.

Here is a quick fix for Ubuntu and Linux users, until Firefox can fix this problem...

(Something similar can be implemented in Windows, but I don't do Windows.)

For Ubuntu/Linux, you are going to create a custom launcher which kills firefox, then waits a second, then opens a new firefox. This custom launcher will replace all your standard Firefox icons for starting Firefox program.

1. Right click on top panel in Ubuntu (or any GNU/linux) > choose "Add to Panel"

2. Choose "Custom Application Launcher"

3. Add following information:

Name: Whatever you want, e.g. Stop and Start Firefox

Command: sh -c "pkill firefox; wait; firefox %u"

Comment: Stop Firefox, Wait, then start Firefox again.

This command will "kill firefox, wait till done, then open firefox".

Now, use your new custom launcher every time you want to use Firefox.

After this, you can choose another favorite icon for your new custom launcher by right clicking on it, choosing Properties, then click on icon image to change it.