Comment 43 for bug 1845801

Problem as described by topic starter also appeared on two computers of mine:
1) An old laptop (Core2Duo and Nvidia GTX260M), that uses Ubuntu from 2015 onwards.
2) A newer desktop (Corei5, Intel graphics card), which started with Ubuntu 19.04. Performed the release upgrade one week after the laptop.
What these two computers have in common, and in common with the other poster: automatic login.
My fix followed the steps of https://askubuntu.com/a/346795 (resume after failed release upgrade):
$ sudo apt-get install -f
$ sudo dpkg --configure -a
$ sudo apt update
$ sudo apt dist-upgrade
$ reboot

It's an error that probably scares new users, so idd, I think it should receive high priority.