Seen on ubuntu 22.04 after do-release-upgrade the xdm Login Manager fails to start, cause a old xdm.pid file hangs from last shutdown on „/run/xdm.pid“. XDM prevent start on a old PID File!! Workaround edit Roots crontab to purge it: sudo crontab -e @reboot rm -rf /run/xdm.pid > /dev/null 2>&1 quit and save with „:wq!“ ..reboot