Browser will not start up

• If you are trying to run FireFox for the first time, then you should look at the FireFox FAQs.
• If FireFox used to work correctly, but it no longer starts when you try to run it, then this article may help.

How to Make FireFox Start

1. Completely close FireFox.
2. Make sure FireFox is not running in the backround.
   • In Windows, hit Ctrl+Alt+Del, open the Task Manager, view Processes, and make sure firefox.exe is not there. If it is, click on it and End Process.
3. Browse to your profile directory. For information about profiles, see the FireFox Profile Tips.
   • In Windows, look in C:\Documents and Settings\<Windows user name>\Application Data\Phoenix\Profiles\<Profile name>\********.slt
   • In Linux, look in ~/.mozilla/<Profile name>/********.slt
   • In MacOS X, look in ~/Library/Phoenix/Profiles/<Profile name>/********.slt
4. Delete XUL.mfl from your profile. This file will be regenerated next time you start FireFox.
5. If you are getting the "default profile is in use" error, delete the parent.lock file.
   • If it does not let you delete the file, then either Mozilla is still running or another program is using it. You will have to reboot to free up this file.
6. Try running FireFox. If it still does not work, reboot and try again.
7. If FireFox still does not work, then more drastic measures may have to be taken. Before continuing, be sure to backup your profile.
8. At this point, it is usually best to create a new profile. For this, completely remove your profile directory and try running FireFox again.
   • Alternatively, you may try "Clearing Extensions and Themes" below.

Clearing Extensions and Themes

• Attention: This section is usually a last resort for someone trying to save their profile. If possible, it is recommended that you create a new profile instead.
• Be sure to backup your profile before attempting this.

1. Delete the chrome folder (and any subfolders) - which will remove most extensions and themes.
2. Delete localstore.rdf - which will remove most UI changes, including those made by extensions.
3. Delete local downloads.rdf , history.dat , cookies.txt , cookperm.txt , user.js , prefs.js , signons.txt , and key3.db
   • This will remove most of your settings and passwords!
   • You can try skipping this step if you want.
4. Try running FireFox. If it still does not work, then you will have to create a new profile or reinstall the FireFox program itself.
5. Create a new profile. Before this, be sure to completely remove your current profile folder.

FireFox Still Won't Start

1. Make sure to backup your profile and then completely remove your profile folder.
2. Uninstall FireFox and verify that the FireFox folder no longer exists.
3. Reinstall FireFox.

FireFox Starts But My Settings Are Gone

• If you backed up your profile, then you should be able to simply copy the backed up files to your new profile. See profile tips for help on doing this.
• If you are missing themes or extensions, you will probably have to reinstall them from scratch. Go to the Tools->Options menu to install and configure extensions and themes.