I specifically need to be on Firefox 86 or lower, but Firefox was updated automatically without my consent and as a consequence I became unable to do the work I needed to be able to do. I tried reinstalling Firefox 86, but after doing so I got this very EVIL message telling me that I had to create a completely new profile without any access to ANY of the open tabs, extensions, settings, bookmarks, etc. It was all just gone! I tried copying the data from the old profile to the new profile, but then it tells me - again - that I have to create a new profile. So then I tried creating a separate installation of the Firefox version that it was updated to and tried copying the profiles over. I then went into about:profiles to load the profile up and at least there the bookmarks and history and passwords were restored. Instead a single tab opens up that says "invalid URL". The session stored in jsonlz4, but I can't get the data out of it now. So is there any way to get my data back? First I'd like to recover the old session data on the updated session since, worst case scenario, I guess I could just manually copy and paste every single tab over. Then I'd like to figure out how to copy all the history and stored passwords from the new installation back to the old installation so I can resume what I was in the middle of working on. Which, again, HAS TO BE on Firefox 86. And then how do I STOP Mozilla from doing this to me again? It's MY COMPUTER and I have a LEGAL RIGHT to decide what is installed and when. I do NOT CONSENT to my data being destroyed bcause some developer doesn't understand the concept of consent and I could care less about any arguments about security (I've heard them all before) if it means giving up the ability to use programs that depend on specific versions of firefox entirely. If the end user wants to take that risk that's for the end user to decide. NOT Mozilla. I would rather choose to update only after reviewing what extensions would break as a consequence of the update and only after deciding for myself that it's suitable for me and if I can't do that I want to make sure it's impossible for Firefox to ever be updated ever again. At present the only thing I can think to do is to start backing up the entire profile directory before going to bed each night and if Firefox updates again I guess I could just reinstall and restore the backup created at that time, but it's a real stupid workaround to have to do.