With all the fanfare surrounding the release of Firefox 3 and the setting of a new world record for downloads, the fact that many people are having problems with Firefox instability seemed to get lost in the shuffle… so I decided to write up a list of troubleshooting methods that might help solve your problems.

There’s a number of reasons for Firefox 3 crashing, which could include any of these, or be something else:

  • Incompatible or Buggy Extensions
  • Buggy Plugins
  • Upgrading an Old 2.x Profile to 3.0 (using a fresh profile works best)
  • Spyware/Viruses
  • Compatibility Problems with XP
  • Video Card Drivers (Make sure you are not using old drivers)
  • Tablet PC Incompatibility
  • Sneezing loudly

You’ll have to read through the article and go through the steps that might apply to you… the last, and potentially best, option is to completely uninstall Firefox and remove all your profile folders, and then install it again, which we’ve covered below.

Run in Safe Mode

One of the first troubleshooting steps you can do is to run Firefox in Safe Mode, which will run without add-ons or extensions. Just look in your start menu, and you’ll see an item for it:


or alternatively, from the command line:

firefox.exe -safe-mode

If Firefox no longer crashes while running in Safe Mode, then you know you have an issue with one of the following:

  • Plugins
  • Extensions
  • Settings
  • Profile

If safe mode does not solve your issue, then you should try to use compatibility mode (mentioned below), and do the uninstall completely and reinstall method. You should also check the “Other Known Issues” section below.

Create a New Profile (if Safe Mode Fixes Your Issue)

Open up a command prompt, or simply type in the full path to firefox.exe, and add on the -profilemanager switch at the end to launch the Firefox “Choose User Profile” screen, where you can create a new profile or switch to a different one.

firefox.exe -profilemanager

Creating a new profile will give you a “blank slate”, where you might have less issues. You can export your bookmarks from the current profile and then import them into the new profile (covered below).

Note: This method usually solves any problems caused by upgrading an old profile to a new one.

Disable Unnecessary Plugins

One of the quickest ways to crash Firefox (or any browser) is to run with a plugin that is causing problems. Open up Tools \ Add-ons, and then go to the Plugins tab, and disable anything you don’t actually use.

For troubleshooting purposes, you could just disable all of them… this is especially helpful when Safe Mode fixes the issue. If Firefox works fine after disabling all the Plugins, then you can enable them one by one until you figure out which one caused the errors.

Note: For me, disabling Silverlight fixed a lot of the crashing issues.

Disable Unnecessary Extensions

In the same screen as above, you can also disable extensions. If running in Safe mode keeps you from crashing, you should go through and disable all your extensions, and then enable them one at a time until you find the one causing the problem.

Clear Out the Caches

There’s a known problem with the download history becoming corrupted and causing crashes when trying to download files. You can just open up the Clear Private Data from the tools menu, and clear out all of the junk at once.

This is a good idea to do every so often anyway, and it can’t hurt.

XP Users: Run Firefox in Compatibility Mode

Some Windows XP users might experience crashing issues that can be solved by using Compatibility Mode. Just right-click on the shortcut and choose Properties, then the Compatibility tab.

Set the compatibility back to Windows 2000, and it might solve the crashing issues for you. Note that setting compatibility in Vista doesn’t seem to help as much in my testing… but your mileage may vary.

Do NOT Use the Tablet PC Input Panel (or OnScreen Keyboard)

I’ve had crashing problems for the last few months, starting from beta 2 and continuing all the way through the release. The infuriating thing was that I could copy the profile to another machine, and it would work fine. I’d create a blank profile, run in safe mode… and Firefox would crash on me every 2 minutes.

I finally figured out the problem… I’ve got a Wacom Intuos3 tablet hooked up to my computer, which enables the Tablet PC Input Panel in Vista, which caused the problem even if it was docked in the background.

The second I disabled that panel, Firefox stopped crashing. If you have the same issue, you can test by opening up Services and setting that service to disabled:

You can also remove Tablet PC components from the Add / Remove Windows Components in Control Panel. I’ve also heard of problems with the standard on-screen keyboard, but I haven’t confirmed those.

Note: I tested this out on two machines… same exact issue. It’s very frustrating, because I really liked having the tablet components.

Other Known Issues

There are some known issues that have already been solved by the good folks over at Mozilla, including these:

  • System Clock is Off
  • Particular Plugins or Extensions that are known to be incompatible.
  • Old versions of Google Desktop
  • Corrupted Downloads cache (solved above)
  • Crashes viewing Yahoo! Mail (solution)

For more information, you can always check the mozillaZine page and the Firefox support page covering crashing issues.

Completely Uninstall, then Reinstall Firefox

This is the last, but best option. What we’ll do is completely uninstall Firefox, and then even clear out the profile folders to make sure there are no traces of any old or broken installations, and then we’ll reinstall.

The first thing you want to do, of course, is make sure that you have backups of everything… so keep reading.

Manually Backup Your Bookmarks and Saved Passwords

I always like to manually backup the two things I’m worried about: my saved passwords and my bookmarks. We can easily backup the bookmarks from Firefox directly, but to backup the passwords we’ll need to first install the Password Exporter extension (provided that Firefox doesn’t crash too soon)

Once you’ve installed it, open the Add-ons window and click the Options button on the extension.

Now you can simply export the passwords using the button (and encrypt if you so choose).

To backup the bookmarks, open up the Organized Bookmarks item on the menu, and choose Backup from the “Import and Backup” button/menu.

Make sure to save both of the files out to a safe place before continuing.

Backing Up with MozBackup

You can also backup your entire profile using the MozBackup utility, which I highly recommend, since you can make sure that you have a total backup of everything in your profile. It’s a simple matter of choosing Firefox in the first screen…

Then choose which profile to backup, if you have more than one… note that the default save location appears to be under “Documents”

Then choose what you actually want to backup… I’d recommend just backing everything up.

Note that if you use this to restore later, there’s some chance that the problem would re-appear because the issue is in a setting. Thankfully we can choose exactly which settings to restore from the file, so there’s no harm in backing everything up.

Uninstall Firefox

Depending on your operating system, you’ll either have to go into Add/Remove programs or “Uninstall Programs”, then find Mozilla Firefox in the list, and choose Uninstall.

Now you’ll want to get rid of any saved profiles, since the problem could likely be there. In XP or Vista, you can find your Profile folder by typing the following into the location bar (other operating systems can check here)


Now what you’ll want to do is either just move that folder somewhere else, or you could outright delete it if you were so bold. I prefer to move it somewhere else in case I need the files again.

Install Firefox Again

Now you can simply install Firefox again, and start over with a completely clean slate. To import your passwords or bookmarks, just use the same menus that you used above to backup, but choose the restore options instead.

Hopefully one of these solves your problem… if you have another solution, be sure to leave it in the comments to help others that might be experiencing something you’ve solved.

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Lowell is the founder and CEO of How-To Geek. He’s been running the show since creating the site back in 2006. Over the last decade, Lowell has personally written more than 1000 articles which have been viewed by over 250 million people. Prior to starting How-To Geek, Lowell spent 15 years working in IT doing consulting, cybersecurity, database management, and programming work.
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