Ubuntu hangs on boot after blackout- Detect the available GPUs
I fixed the problem in the following way:
- Boot in recovery mode with read/write access
- Go to shell as root
- sudo apt-get remove lightdm (now gdm3 is default)
- Start the network: sudo service network-manager restart
- sudo apt upgrade
- reboot
For me that worked. Can be that it would have even worked if I didn't remove lightdm.
I just had to boot into recovery mode and run update-grub to repair the system.