August 3-4 Ubuntu offered an update. It was not at all clear going in that it was a major version change, being a jump in major Linux version from 5.19 to 6.2.
At first it booted as usual with a notification in 'system tray' that reported broken packages. I followed the suggestion to remove and reinstall those packages and was left with a box that will only boot into command line mode.
Furthermore, reversion to previous version fails in the same way: no NVIDIA drivers available where they used to be.
Using recovery mode menu to run dpkg tells me there are no packages available for NVIDIA GeForce video card, and libglmesa. Also Zoom fwiw.
I would prefer not to start from scratch here. Anyone have any helpful pointers on how to patch this back up?
Date: 4 August 2023
Event: Ubuntu driven auto upgrade
From Linux 5.19 to 6.2 in jammy 22.04LTS
Video card: NVIDIA GeForce
Drivers missing:
NVIDIA 470 series, and others
Answer (h/t Rinzwind)
Reinstalling the desktop:
apt-get install --reinstall ubuntu-desktop
Applied at the command prompt in the newer version, it restored the use of the desktop on both the updated version with Linux 6.2 and the previous version with Linux 5.19.
Jammy is unjammed!