You seem to be running the Firefox version from the Ubuntu repositories. It is quite possible that this version behaves differently that the official version from the Mozilla server, so you can give that version a try.

• https://www.mozilla.org/en-US/firefox/all/

Normally it should be sufficient to remove the checkmark on "Always use Private Browsing mode" and restart Firefox when requested. If that isn't the case then there might be a startup parameter on the command line that starts Firefox or you may have a user.js file or an extension that forces Private Browsing mode. You can try to disable the Ubuntu extensions.

You can also check the browser.privatebrowsing.autostart pref on the about:config page.

couple of things. First, I am running with 50.0.2 which, from the mozilla site, is the latest and greatest. I went to the safe mode and removed the checkmark and restarted. When I did that the setting magically changed to "remember no history". Its still set to that as it actually allows me to see sites.

This all started with sonarr which magically changed to a skelton of that program. I then sent it to the sonarr folks, before I knew what was going on and they replied immediately with asking if I had private browsing on. That is when I started to try and fix my problem. If you can tell me how to fix I would be delighted to do that.

Oh, I guess I should also mention that I have been building and programming these things for over 30 years so I have some small knowledge of how its supposed to work. My basic problem is that this thing seems, to me, to be a moving target. I can, however, follow directions.

First, I am running with 50.0.2 which, from the mozilla site, is the latest and greatest.

Yes your Firefox software originates from Moxilla but yours will be the canonical version built by Ubuntu. Use

MenuButton {3bar icon) -> Help {(?) icon) -> About Firefox 

You will notice it mentions Ubuntu & Cononical The forum software picks up your UAS as

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0

I do have that installed myself on a Ubuntu 16.04 machine. I also have a build direct from Mozilla and that shows

Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0

Niether of them have any issue with turning off Private browsing, or allowing the default remember History.

You do have quite a few Firefox extensions as add-ons, it may be worth testing in Firefox's safe mode to see if that helps

• Diagnose Firefox issues using Troubleshoot Mode

If I try and goto safe mode, for instance, and set it to use private browsing and set everything to remember history it reboots to never remember history.

What happens if you use Safe Mode but do NOT use Private Browsing does Firefox work ok and as expected like that. (Do not reboot that will take it our of Safe Mode)

What did you mean by:

If I set it to remember history the program screws EVERYTHING up

What happens or does not happen ? and why do you consider that is because you have set Firefox to remember History ??

I am not sure what sonarr is, some sort of bit torrent service possibly. Is that the only thng that is causing problems ?

I did all the things you suggested to no avail. then I went to another machine and found that none of those problems existed. On the problem machine the only way I can make firefox work is to stop all history. Anything else and it goes nuts. I have also tried to remove and reinstall. Same problem. I think that my problem is not a problem with firefox but something else. This also means I have wasted your time and, for that, I apologize.

thank you for your help - you can remove this whole thing or mark it solved (whatever)

A plain uninstall and reinstall often does not solve anything.

If the problem is with the program files then you need to first of all delete those files before reinstalling.

• See Troubleshoot and diagnose Firefox problems_5-reinstall-firefox
• (Make sure it is the Linux version of the article https://support.mozilla.org/kb/troubleshoot-and-diagnose-firefox-problems#firefox:linux:fx50 ) I will check later to see what the default location is of the program files for the Canonical build in Ubuntu.

More likely it is a problem with the Firefox profile. Try using a new additional profile.

• See Profile Manager - Create, remove or switch Firefox profiles

If that works we will then need to figure out what happened that causes the problem & fix the original profile (If that contains important bookmarks etc.)