This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

How do I go back to 4.0 after upgrading to 4.0.1 ?

  • 1 reply
  • 2 have this problem
  • 1 view
  • Last reply by Xircal

bettyc1234
bettyc1234
more options

I upgraded to version 4.0.1 two days ago. I haven't been pleased with the performance (frequent freezes, slow loading), and one of my favorite tools that I need for work doesn't work properly. I'd like to uninstall the upgrade and go back to 4.0. How do I do that?

I upgraded to version 4.0.1 two days ago. I haven't been pleased with the performance (frequent freezes, slow loading), and one of my favorite tools that I need for work doesn't work properly. I'd like to uninstall the upgrade and go back to 4.0. How do I do that?

All Replies (1)

Xircal
Xircal
more options

That's not a good idea. See: Security issues fixed in Firefox 4.0.1

You can revert to the previous secure version if you wish which is 3.6.17 as follows:

  1. Go to Download Firefox v3.6.17 and download it to the desktop.

  2. Then go to Add/Remove Programs, scroll down to "Mozilla Firefox" and remove it, choosing to keep your bookmarks, customizations etc., (don't checkmark the box).

  3. Then reboot and delete the folder called "Mozilla Firefox" at this location: C:\Program Files\Mozilla Firefox

  4. Finally run the installation file you downloaded to the desktop earlier.

Your bookmarks, customizations etc., are maintained in a different location and will become available to you again once you complete the installation.

After you complete the installation, go to the Plugins Check page and update where necessary.

I would suggest in the first instance though to perform a standard diagnostic to correct the anomalies. See: Basic troubleshooting