Out of the box, Ubuntu 20.04 identified the correct Nvidia driver to use automatically.
However, according to the apt package manager, the driver (whilst in active use) wasn’t installed and some of the various underlying libraries were marked as no longer required (incorrectly!).
sudo apt autoremove would delete off these various Nvidia libraries and cause the next boot to fail.
apt-mark (in an attempt to mark the package as manually installed) wasn’t possible either because apt didn’t know about / couldn’t find the Nvidia driver package that Ubuntu was using.
The ultimate fix was to manually install the driver, forcing it to be marked as “manually installed”.
sudo apt-get install nvidia-driver-460
Problem with auto-updates
Booting trouble free for many weeks, my machine then unexpectedly failed to boot. I got the dreaded black screen with a single message:
dev/sda1: clean, 552599/6111232 files, 7119295/24414464 blocks
I suspect, although can’t be sure, that a package upgrade had indirectly affected the nvidia driver.
The solution was simple:
sudo apt-get purge nvidia*
sudo ubuntu-drivers autoinstall
Many thanks to the various answers here: https://askubuntu.com/questions/882385/dev-sda1-clean-this-message-appears-after-i-startup-my-laptop-then-it-
Frank Ray & Associates is a software engineering consultancy that builds high quality software for businesses.