After becoming frustrated with seeing Nautilus appear when I had set Nemo as the file manager, I decided to uninstall nautilus from Zorin OS 16:
sudo apt uninstall nautilus
Then, as I watched all the other stuff get nuked I thought to myself, I better reboot, so I link the action to the outcome which was coming to me: Now I see a black and white terminal login. Running startx does not work. Running lxsession does not work. Then I had an idea: run /usr/bin/gnome-session this seems to pause and then return to terminal doing nothing. Takes about 2 seconds to do this.
Oddly I can't ssh in anymore. Going to the machine ssh isn't running. I reinstall it openssh-server. From another machine I notice the machine's key has changed / regenerated. Odd.
So I
sudo apt install gnome-session
This does something.
But still nothing.
About to following the instructtions at How to remove nautilus without screwing up unity? - Ask Ubuntu but then I realised it is from December 2015 and maybe I should post in the Zorin forum be a little more relevant me thinks.
So... any ideas my next step? Most likely I have a snapshot as the system is on btrfs however I think I'm only on weekly backups which would be sub-optimal solution.
Should I:
fix it somehow?
revert to snapshot? (likely!)
reinstall Zorin OS? (prefer not)
UPDATE I so restored system using timeshift back 15 days to Sept 29 2021. After updating various apps, I was back in action in only about 5 hours. Amazingly how many updates happen in 15 days. Still though, it would almost be worth patching apt with a warning about uninstalling nautilus but I guess I should be more careful.
DUDE! You have a snapshot! You were lucky enough to think of that ahead of time! Well, whats to think about! Revert Snapshot! Lets go, what are you waiting for soldier, we gonna fix this system the easy way woohoo, you are freaking stellar Tomachi!
Because the 2nd easy way, that would take longer, is re-installing Zorin OS 16.
And the 3rd way, only Aravisian knows, cause its the overly complicated, tons of terminal commands, in only hope that it might work and fix it solution.
So ya, lets do the Snapshot method. Gosh, if only more of us were like you, and made our backups. Even I admit I am guilty of not have even made a single backup of my systems. Oh I know I know, I am glutten for the possible future punnishment.
But what can I say, I am one of the laziest tech support technicians you've met. HAHA
