Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can use one of these to start Firefox in Safe Mode:

• On Windows, hold down the Shift key while starting Firefox with a double-click on the Firefox desktop shortcut
• On Mac, hold down the Options key while starting Firefox
• Help > Restart with Add-ons Disabled

• https://support.mozilla.org/kb/Safe+Mode

You can also do a check for corrupted and duplicate fonts and other font issues:

• http://www.thexlab.com/faqs/multipleappsquit.html - Font Book 2.0 Help: Checking for damaged fonts
• http://www.creativetechs.com/iq/garbled_fonts_troubleshooting_guide.html

We're sorry to hear that Firefox is crashing when you open it. Please do the following to give us crash IDs that will help us understand more about the crash.

1. (OS X 10.6 or previous) Click the Finder icon in the dock. Your home folder will be selected. In the right side of the window, click the Library folder to open it. Then open the "Application Support" folder, the "Firefox" folder, the "Crash Reports" folder and finally the "submitted" folder.
   (OS X 10.7 or above) Click the Finder icon in the dock. On the menu bar, click the Go menu, hold down the option or alt key and select Library. A window will open containing your Library folder. Then open the "Application Support" folder, the "Firefox" folder, the "Crash Reports" folder and finally the "submitted" folder.
2. Open the 5 most recent files with a text editor and copy the IDs.
3. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

I encounter the same problem. I suspect this has to do with remote user homes. Firefox 24 works on local accounts - not in server hosted ones. I am sorry i can not provide crash reports because Firefox hangs in such an early state - it does not write crash logs. It literally does not crash - it just stops to respond a lounchtime - so it does not give an error in the system console, too.

We have 20 Workstations (OSX 10.8.5) working with apple remote user homes. the problem is persistent on all systems. Firefox 23 worked fine and does again if you reinstall it.

Thanks Cor-el, I have tried starting Firefox in safe mode. But it still hangs. The fonts have been checked, but there were only 40 minor problems identified. Said to proceed with caution. I didnt know what would happen if I deleted those fonts so I didnt go ahead to delete them as they were classified as minor problems.

Thanks Waka_Flocka_Flame. Unfortuantely I have deleted the Firefox application support files in my attempts to reinstall a clean version. The current crash report file contains only 2 documents InstallTime20130618035212 and 20130910160258. Each has 1 number only in the file, 1381029719 and 1381030658 respectively. Sorry!!

Thanks Benlo, It sounds like we have the same problem. I might need to use Safari ( dare I say it ).

Benlo, do you have any crash reports?

This really helps us get a look at exactly whats wrong.

Also see: Mozilla Crash Reporter

Sorry Waka_Flocka_Flame, Firefox does not really crash. It gets stuck. After updating to v24 it checks the plugins which takes considerably longer than normal (factor 5) after this is done the program does not crash but stops responding (e.g. Dead process, Wheel of death). Thus it does not create a crash log.

Try to disable hardware acceleration by editing prefs.js

If you need to find your profile and the path to that file, see the Profiles - Where Firefox stores your bookmarks, passwords and other user data article.

Add these two lines using a text editor, save the file, then try to start Firefox, does it work now?

user_pref("gfx.direct2d.disabled", true); user_pref("layers.acceleration.disabled", true);

No change, i am afraid.

Does loading the profile manager and creating a new profile work.

• Profile Manager - Create, remove or switch Firefox profiles

Yes, this does work. One can edit, create and delete profiles. Starting Firefox results in the same stall, though.

By the Way: If you kill Firefox in its stalled state afterwards the used Profile is corrupted and has to be removed. I think FF24 writes or locks some of the profile files and FF23 can not access them any more.

Try to remove all places.sqlite file(s) in the Firefox profile folder to make Firefox rebuild the places.sqlite database from the most recent JSON backup (bookmarks-####-##-##.json) in the bookmarkbackups folder.

Also make sure that your security software is locking any files in the Firefox program folder.

• https://support.mozilla.org/kb/The+bookmarks+and+history+system+will+not+be+functional
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Thanks, cor-el. This gets me around deleting my whole profile folder every time :-)

See this recent thread posted on MozillaZine:

• http://forums.mozillazine.org/viewtopic.php?f=38&t=2754491 Firefox wont start on Mac connected to Server

...which links to the following:

• Bug 918612 - Mac: Firefox 24 doesn't start when home directory is on AFP network share
• Bug 879133 comment 38 (workaround)

I can definitely confirm that this is only happening in our office to Mac users with their home folders on the server. It has always worked in the past. Starting with Firefox 24 it hangs and never recovers. Use a local user on the same machine, and it works fine. The users are on 10.6.8 on fast iMacs.

Thanks Alice, Sounds like a promising solution but dont know how to change location of profiles. Maybe I'll just wait until a new version of Firefox comes out with a fix.

SamK, Hopefully bug 918612 will be fixed soon.

If it takes too long for the bug to be fixed, you can change the location of a Firefox profile as follows:

1. Create another Firefox profile and choose a new, empty folder on your local hard drive for the profile location. Instructions are here: Profile Manager - Create, remove or switch Firefox profiles
2. Copy important data, if you wish, from the old Firefox profile folder to the new Firefox profile folder. See: Recovering important data from an old profile

For other ways to move the profile see http://kb.mozillazine.org/Moving_your_profile_folder

I found a workaround for OSX 10.8.5 and Firefox 24.

1) Go to Finder and look into Applications.

2) Open the context menu for Firefox and select "Display Package Contents" or a similar option (I'm translating from Spanish).

3) A new window should open and look for an icon called "Updater".

4) Double-click on Updater and it will launch the installation the latest Firefox update, fix the problem.

I think this happens possibly because the user at some point ignored an update message or the message simply failed to show up. Either way, this fixed the problem for me.

Starting with version 24, Firefox fails to read the user profile from network home shares. The only working solution at present is to move the profile files to a local hard drive and setup a symbolic link to point to it.

Hopefully this will be fixed in future versions.