If your system is so messed up that you need to revert to earlier versions constantly then why did you become a tester? I am pretty sure that once Firefox 4 Final was released the removed all the betas. Unless some third party site still has a copy then you are out of luck.

I am sure someone will figure out what you have done. From what you say I do not know if you have used default installs or custom installs. It is relatively easy to install Firefox and probably easy to solve your problems about installation not working when you try to upgrade. I imagine archived copies of old builds are likely to be available, but probably will be unnecessary.

The first thing you should do is look for your firefox profiles, and back them up by copying them elsewhere. You can find the profile by using

• Help -> Troubleshooting information | profile directory [open Containing folder]
• Do that separately for each user account

Did you set up separate profiles for each version of firefox ? eg by using profile manager if you did then there will be two sets of user data so two lots of history bookmarks and passwords.

If you did not then all you have is one set of profile data. (I am assuming it is a single use computer, and does not have multiple user accounts). Do you have separate user accounts on your machine ? (what shows up on the welcome screen)

Have you any particular reason to get back specifically the firefox beta as a browser, or is it the userdata that it has collected that is of importance to you ?

Are you currently able to see and use all the important user data, bookmarks etc, when you use Firefox, or do you think some of it is unavailable ?

It turns out I was just dumb. I had thought I remembered a feature in the beta 12 that was not in the 4.0. I see now that I was mistaken, and you are right, I have no need for the beta 12. I really don't think my system is messed up. Everything else always works fine. Just the updates Firefox sends that will not install. And like I said, over time I realized that I can go to their website, download the update, and install it, and it runs fine. Thank you so much for your help.

Yes, Firefox does install easily as long as I go to the website and download it myself. And yes, I do have just one Firefox profile. Yes, it is a single use computer, no multiple user accounts--just me. Yes, I can see all the bookmarks, etc., --everything that is always on Firefox is still here. I'll just continue to go to the website for the updates and do that myself. It's so convenient just to let Firefox take care of that, but that feature hasn't worked for me for 4 or 5 years, and I will just have to consider it a luxury that I will have to do without. Thank you so much for your help.

One thing I do wonder about is whether you have actually retained two versions of firefox, possibly inadvertently after using the Beta channel.

As you say it is working if you use the manual installs. If you do continue to have problems with the automatic updates it may be worth reading Software Update failed