Today, i try to upgrade a PC from Ubuntu 17.04 to 17.10.
Ubuntu 17.04 was recently install with no particular specific option on this PC. Note : I have install open-ssh as server, and I have success ssh connection from an other PC to this PC. I have configure my desktop to be automated lock after 5 min of inactivities.
I start upgrade with update-manager. I have answer to firsts questions and then I enter to phase "download and install package". I go away from the PC.
Few minutes after (10, 20 ?) I come back on my PC, there is the lock screen (with a new background image). It's normal, this is the automtic lock. But it's impossible to unlock, my password was refused.
I try to come back on a text terminal (ctrl-alt-F7 + alt-F1) : impossible.
I try to reboot. It's reboot. I have the "standard login screen". I enter my password, screen switch to black 1 seconde, as a succesfull login, and then I come back to login screen.
I try to have a terminal (ctrl-alt-F7 + alt-F1) : impossible.
I try to connect by ssh from an other machine : impossible.
So, right now I restart reinstall ubuntu from scratch, from an USB key.
But I have question for my other upgrade : should I disactivate automatic lock screen before upgrade ?
Best regard Emmanuel
Had the same issue. I used the "switch to user" menu item and selected the current logged user and could unlock the session.
The Problem was with GDM. Try installing lightdm. There will be a prompt in the installation screen. Please choose lightdm and you will have your login screen altered, similar to 17.04's.