This article will show you how to upgrade to Firefox 3. After upgrading, you will still have your existing information such as bookmarks and passwords; however, some extensions and themes may temporarily not work after upgrading, because they might not be updated for Firefox 3 yet.

Firefox 3 is the latest version of Mozilla Firefox. It includes many new features, and fixes a lot of issues covered in the Firefox Support knowledge base. For a list of common support issues which can be fixed by upgrading to Firefox 3, see Common issues fixed in Firefox 3.

Installing

Before installing Firefox 3, make sure your computer meets the system requirements. Firefox 3 requires at least Mac OS X 10.4.

Note: You should back up your information before upgrading to Firefox 3.

Download Firefox 3 from the Mozilla Firefox page and install it. For information on how to install, see Installing Firefox. Firefox 3 will replace Firefox 2 unless you install it in a custom location.

Having problems?

• Cannot connect after upgrading Firefox
• Firefox is already running but is not responding
• Firefox will not start

If you have both Firefox 2 and Firefox 3 installed and you want to stay with Firefox 3, you should uninstall Firefox 2 to prevent unusual behavior and data loss when switching between versions.

Reverting to Firefox 2

If you revert to Firefox 2, you will lose any information saved since upgrading to Firefox 3.

1. Uninstall Firefox 3. Do not check Remove my Firefox personal data and customizations..
2. Restore your backed up information.
3. Install Firefox 2 if you uninstalled it. See Installing Firefox for instructions.

More information

• Firefox 3 release notes
• Firefox 3 for developers
• Firefox 3 release schedule