I think I've solved it. I removed gdm3 and lightdm apt purge gdm3 apt purge lightdm
then reinstalled gdm3 and ubuntu desktop. apt install gdm3 ubuntu-desktop It now seems to be working as expected. It appears to me screen blanking may not work with lightdm, but I'm not sure perhaps it was something else held over form 18.04. Just switching from lightdm to gdm3 caused a "Low Graphics Mode" error, removing and reinstalling gdme3 solved that. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1905982 Title: Screen not Blanking after upgrade to 20.04 Status in gnome-shell package in Ubuntu: Incomplete Bug description: After a do-release-upgrade from 18.04 to 20.04 screen blanking stopped working. I had my desktop set to blank but no lock the screen. After the upgrtade it does not ever blank. preferences are set in Settings-> Power -> Blank Screen 10 minutes Automatic Suspend is OFF gnome-screensaver is running gnome-screensaver command -a doesn't do anything. video driver is Nvidia-455 Display Manager is lightdm switching to gdm3 causes the video to not work properly. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1905982/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
