From MozillaZine Knowledge Base

If Firefox or Mozilla Suite/SeaMonkey fails to start then this article may help.

• If it starts up but won't load any web pages, then read Error loading websites.
• If it starts up but immediately closes (either with or without an error message) see Firefox crashes.
• If it starts up but immediately hangs (stops responding) see Firefox hangs.

Profile locked

One of the following messages can appear when you start your Mozilla browser, if the profile is inaccessible or "locked":

• Profile in Use: The Profile Manager appears along with a message that the selected profile is already "in use" when you attempt to start your Mozilla browser.
• Close Firefox: A "Close Firefox" box appears in Firefox 1.5 or above, with one of these messages [1] (Starting in SeaMonkey 2, a Close SeaMonkey box may appear with a similar message):
  • "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."
  • "A copy of Firefox is already open. Only one copy of Firefox can be open at a time."

Ending the browser process or restarting the system will normally unlock the profile. If not, see this article article for further instructions.

Windows-specific problems

Procedure entry point js_SaveRegExpStatics error in js3250.dll after updating Firefox 3.5

Firefox 3.5 may fail to start after updating and you may see the error, The procedure entry point js_SaveRegExpStatics could not be located in the dynamic link library js3250.dll. [2] (For other update errors see the Software Update article.) As a temporary workaround, open the C:\Program Files\Mozilla Firefox folder, look for two "js3250.dll" files (the second one will be named "js3250.dll.moz-backup"), rename "js3250.dll" to "Xjs3250.dll" and then rename the backup file to "js3250.dll". This should allow Firefox to start but you will still need to update Firefox. If the problem persists, download the Firefox setup file from www.mozilla.com, remove the "Mozilla Firefox" program folder and then reinstall Firefox. [3]

Firefox 3.5 does not start after updating with ZoneAlarm ForceField enabled

If you use ZoneAlarm ForceField (either standalone or as part of ZoneAlarm Extreme Security) Firefox may crash at startup or fail to start after an update. Try clearing the ZoneAlarm virtual cache (go to "Browser Security -> Settings -> Advanced", and click "Clear Virtual Data" in ZoneAlarm Extreme Security [4]) or turn off Forcefield and restart Firefox. [5] If the problem persists, download the Firefox setup file from www.mozilla.com, remove the "Mozilla Firefox" program folder and then, with ZoneAlarm ForceField turned off, reinstall Firefox. For other suggestions, read this article and see this ZoneAlarm forum thread, or contact ZoneAlarm Support.

Firefox 3.5 does not start when System Mechanic is installed

Firefox 3.5.x may fail to start if the Iolo System Mechanic application is installed. You may see an error message similar to: Firefox.exe - Application Error. The instruction at “0x5a9288f8” referenced memory at “0x5a9288f8”. The memory could not be “written”. (the memory address varies). Internet Explorer 8 or other browsers may also fail to start. See if updating System Mechanic fixes the problem or, if don't need the program, consider uninstalling it. As a workaround, try disabling the two System Mechanic services. You can also try renaming the "ioloHL.dll" file in the C:\Program Files\iolo\Common\Lib folder. [6] [7] [8] [9] [10]

Firefox 3.5 delayed startup

Firefox 3.5 may take a minute or longer to start up, if a large number of files exist in the Internet Explorer Temporary Internet Files or in the Windows Temp folder. [11] [12] To delete the IE Temporary Internet Files (also called the IE browser cache) go to Internet Options (via Control Panel or from Internet Explorer -> Tools) and, on the General tab, click the Delete... (or Delete Files...) button. More information and screenshots are here for IE6, here for IE7 and here for IE8. To prevent future problems you can reduce the amount of disk space used for Temporary Internet Files to around 100 MB or below if it exceeds that number ("Internet Options -> General (tab) -> Settings"). You may also wish to select the Internet Options Advanced setting, ""Empty Temporary Internet Files folder when browser is closed". If Firefox still takes a long time to start, go to "Start -> Run" (or "Start Search" on Vista), enter %temp% in the Run (or Start Search) box to open the Windows Temp folder, delete the contents ("Edit -> Select all", "File -> Delete") and then empty the Recycle Bin. This issue should be resolved in the Firefox 3.5.1 update (bug 501605).

Firefox 3 will not open if started from an Internet shortcut or another application

If you have more than one Firefox profile, clicking on an Internet shortcut or a Web link in another application will not start Firefox 3 if you have not set the Profile Manager to automatically start Firefox with a selected profile. This is a known issue in Firefox 3 which should be fixed in Firefox 3.0.2 (bug 395891). As a workaround, open the Profile Manager, select a profile, place a check mark in the "Don't ask at Startup" option and then start Firefox with that profile, to set it as the default.

Firefox does not start after installing the WinAmp Toolbar

Firefox may not start after installing the WinAmp media player, if the toolbar option is selected during installation. [13] [14] You will need to Start Firefox in Safe Mode then uninstall the WinAmp Toolbar via the Firefox Add-ons manager ("Tools -> Addons -> Extensions").

Application fails to start because js3250.dll or other program files are missing

If you see message, This application has failed to start because js3250.dll was not found. Re-installing the application may fix this problem. you must reinstall Firefox (or other Mozilla browser) and check your system for malware. See This application has failed to start because js3250.dll was not found for more information.

"The program must close to allow a previous installation attempt to complete. Please restart." on Vista

If you are receiving this message when attempting to start Firefox and a restart has no effect, delete the “xpicleanup.dat” file, located in the C:\Users\<username>\AppData\Local\VirtualStore\Program Files\Mozilla Firefox folder. If you have problems finding or deleting this file, follow these steps:

1. Restart your system, or if you know how, terminate all Firefox and xpicleanup processes with Task Manager.
2. Go to "Start -> Start Search" and type in %APPDATA%.
3. From there, navigate to Local\VirtualStore\Program Files\Mozilla Firefox
4. Delete the file "xpicleanup.dat".

You should now be able to start Firefox. [15] [16]

If the problem persists, restart the system or use Task Manager again, then delete the "xpicleanup.exe" file in the Firefox installation directory (usually C:\Program Files\Mozilla Firefox). [17]

"Error opening file for writing..." on Vista

Firefox may require you to be logged in as an administrator. As a workaround, to launch Firefox, right-click the icon and choose "Run As Administrator".[18][19]

Mozilla Suite or SeaMonkey fails to start

If you've tried running the mozilla.EXE or seamonkey.EXE file directly and you also tried running the Profile Manager, without success, the problem is located within Gecko Runtime Environment (GRE), which means you'll have to reinstall Mozilla Suite or SeaMonkey so that new GRE files are created. Solution:

• Download the Mozilla Suite or SeaMonkey offline installer but do not install it yet.
• Uninstall Mozilla Suite or SeaMonkey using Control Panel, Add/Remove Programs (if both are installed, uninstall both).
• Restart the computer.
• (Mozilla Suite or SeaMonkey 1.0.x) Delete the C:\Program Files\Common Files\mozilla.org\GRE\ folder ....THIS IS IMPORTANT!
• Delete the leftover \Program Files\mozilla.org\Mozilla or \Program Files\mozilla.org\SeaMonkey folder if it exists, and all its contents (save your Plugins folder, if you wish, to a backup location).
• With your antivirus program disabled and all other programs closed, reinstall Mozilla Suite or SeaMonkey.

Ref: ilias.ca (Related bug reports: bug 195600 and bug 211694).

Linux-specific problems

Ownership

If you used "sudo" to install Firefox and it starts at the end of the install process and runs when you log in as root but fails to run as a normal user, then check the ownership of "$HOME/.mozilla" and subdirectories. The symptoms are that you won't get any error messages, and Firefox will exit with a value of 1. The ownership of "$HOME/.mozilla" and subdirectories may be set to "root:root", and you will need to execute

chown -R <username>:<usergroup> $HOME/.mozilla

at the command line to get Firefox to work (Firefox 1.0.x).

Similarly other users on the system may need their ".mozilla" folder 's permissions changed using "chown" as shown above.

Fedora 4 libstdc++

When you run from the console window the command /{path to download location}/firefox/firefox you may see

/usr/local/firefox/firefox-bin: error while loading shared libraries: 
libstdc++.so.5: cannot open shared object file: No such file or directories

On Fedora 4, you need to install libstdc++ by running yum install /usr/lib/libstdc++.so.5. After running this, rpm -qf /usr/lib/libstdc++.so.5 should print compat-libstdc++-33-3.2.3-47.fc4.

"/lib/i686/libc.so.6: version 'GLIBC_2.3' not found required by /{path to download location}/firefox/libxpcom.core.so"

If you see

/lib/i686/libc.so.6: version 'GLIBC_2.3' not found required by /{path to download location}/firefox/libxpcom.core.so

or something similar when starting Firefox, then the library is not new enough to support Firefox 1.5 and possibly previous versions. Updating GLIBC is not advised as other applications depend upon it. If possible, migrate to a newer Linux distribution with an updated version of GLIBC.

Mac-specific problems

Firefox 3 does not start on Mac OS X 10.3.9 or below

Firefox 3 requires Mac OS X 10.4 or above. [20] Mac OS X 10.3 and Mac OS X 10.2 users should install Firefox 2 after first removing Firefox 3. [21]

Other solutions

• Check for problematic extensions.
• Perform the standard diagnostic.

External links

• Firefox will not start (Firefox Support)