I installed ubuntu 18.04.4 LTS 2 days on a desktop with intel processor and integrated VGA, and was downloading and configuring everything how I liked, including xubuntu-desktop, but I was using gdm3. And I had no problem during these 2 days. I did shutdown the computer and reboot many times after the installation and had no problem whatsoever prior to today.
But when I started the machine today it was stuck in this screen for a while. As you can see the last line is "Started Unattended Upgrades Shutdown", but when I rebooted it got stuck again but with a different message. But one thing that they had in common was that it was just after "Started Gnome display manager". When I tried using a tty it wouldn't work, it would be flashing the screen or the characters I type would not come up. I tried choosing an older version of the kernel on grub but nothing changed. After searching a lot online I tried booting with recovery mode, and uncommented the WaylandEnable=false line on /etc/gdm3/custom.conf but still same problem. Than on recovery mode I ran systemctl set-default multi-user.target and I was able to get access to tty after reboot. But when I started gdm, I got the same problem. So I reboot again, set up to use lightdm instead of gdm3, and started lightdm, but now I get a black screen with a flashing underline cursor on the top left corner.
I have been trying to find a solution for this for hours now because I don't want to have to format my machine and have to configure everything again, since that is what I have been doing this last 2 days, and also I have no guarantee that the problem will not repeat itself, given that I don't know what caused it, and most of the configuration I did was pretty basic like installing new software.
