Can I Go Back To Firefox 3.6?

Yes, it is possible to rollback to Firefox 3.6 without too much trouble. However, Mozilla is only going to continue to provide security updates for Firefox 3.6 for a short time (likely until Firefox 5 is released in the summer of 2011). You may run into an issue with your extensions being stuck in disabled status upon starting Firefox 3.6 (see My Extensions Are Disabled section below). To go back to Firefox 3.6 follow these directions:

1. Go to getfirefox.com below the green download button will be a small link All Systems and Languages. Click on this link.
   
2. On the new page on the far right is a link to the most current version of Firefox 3.6.x (when this FAQ was written the most current version was 3.6.16). Click this link.
   
3. Scroll through the list and find your preferred Language and then click the link for your OS (Windows, Mac, Linux)
   
4. Save (do not open/run) the installer to somewhere you will be able to find it later.
5. Close Firefox
6. Uninstall Firefox. Note: Your profile is saved away from the Firefox application and removing Firefox will not remove your profile.
   Windows users DO NOT check the box Remove My Firefox personal data and customizations. Doing so will delete your Firefox profile.
   • Windows: Control Panel (Add/Remove Programs or Uninstall a program)
   • Mac: Drag the Firefox application to the Trash. Firefox also has a .plist file at ~/Library/Preferences/org.mozilla.firefox.plist you may wish to remove.
   • Linux: Remove the firefox Installation directory, usually: /usr/lib/firefox-<version>

     
     

7. Locate where you downloaded Firefox 3.6.x in Step 4 and run the installer
8. Once the installation is complete, launch Firefox.

My Extensions are Disabled

In rare cases reverting back to Firefox 3.6.x after running Firefox 4.0.x can cause all your extensions to be stuck in disabled. To fix this issue:

1. Locate your profile folder.
2. Close Firefox
3. Delete these files (not all files may be present):
   • extensions.ini
   • extensions.cache
   • extensions.rdf
4. Restart Firefox. Firefox will rebuild the extension list and also run a compatibility/update check at this time.