hi, do you have a folder labelled "old firefox data" on your desktop? if you press windows-key+r and open %appdata%\Mozilla\Firefox\Profiles how many folders are you seeing there?

Yes I have the folder. It contains 3911 files and 478 folders. I guessed that I could take the extensions folder and put it into the extensions folder and that gave me all my addons back...some incompatible but I will get rid of those.

I am really worried about my passwords. Where were they stored and how can I get them back? I got the bookmarks by guessing and it also worked. Why isn't there an import for things like this?

Yes I ask questions and I have PTSD.

so before you continue any further you should probably take another backup of that "old firefox data" folder at a secure location. i think you could just replace all the contents of your current profile folder with what's inside old firefox data to get back to your prior state. or you could import stuff selectively: Recovering important data from an old profile

i'm sorry that this happened - this is obviously not an intended action during an update, so something has gone wrong there :-/ did you receive any request to refresh your firefox during the update procedure?

I got a "restart in safe mode" or "restart". I chose restart.

Where is the profile folder? Is it in the profile for my computer? It isn't in the Mozilla Firefox folder.

yes, it's under %appdata%\Mozilla\Firefox\Profiles

Profiles - Where Firefox stores your bookmarks, passwords and other user data

I have looked at most things...I have a lot of passwords and that...but it looks like it is all back. I have "printed" (actually made a pdf of the last post) and am going to keep it.

You have been very patient and helpful.

It did give me an old theme but I can handle that.

One more thing...

Many extensions say they are saying "Not compatible with multiprocess". What does that mean? It also says that multiprocess is nit enabled.

I am getting rid of the incompatible addons also.

firefox is currently undergoing through its biggest technical changes since its inception by switching to a multi-process architecture (different processes for the browser interface, webpages and so on) which should bring better performance, stability and security. because that's such a big change this is only gradually rolled out to users, so far this new architecture is only enabled for users without addons or a couple of known compatible addons, but that will change in upcoming versions... https://blog.mozilla.org/futurereleases/2016/08/02/whats-next-for-multi-process-firefox/

Thank you.