Is it possible you've installed a display manager that isn't compatible with your graphics drivers? I've read that 18.04/18.10 has been causing a lot of trouble in regards to booting up/entering desktop, although more specifically for Nvidia graphics cards. You could try entering recovery mode to change the default display manager there, or if you're using Nvidia trying different Nouveau settings in GRUB (
In reply to your comment: the steps to take for a graphics problem is in the latter half. I actually just ran into the same exact issue as you after installing and subsequently uninstalling
sddm. Unfortunately I didn't document the solution/process well enough to know what fixed it, so this is a shotgun approach.
Try these to fix the login issue:
Preface: my desktop environment is Plasma/KDE. Trying Gnome or Gnome with Wayland would kick me out too. When I tried KDE, it showed an error saying it couldn't write to, I believe
.ICEauthority, in my home folder. Here's what I tried:
I suggest taking a look at the manuals related to your issue:
man chown. You can try taking ownership of files
man startx mention. If possible, posting your
xsession_errors log located in your home folder may help.
These are the steps to take if it's a graphics drivers issue:
try these in the order they're in to see if it's solved.
- Type in
sudo nano /etc/default/grub to begin editing GRUB.
- Look for the line that says quiet splash. Add
nouveau.modeset=0 to the end of that, within the quotes. Press ctrl + O to write it out, then enter to save it. Ctrl + X to exit,
sudo upgrade-grub to really save it. Reboot.
TTY and run `sudo apt remove nvidia* --purge -f -y". Reboot.
- Add the proprietary gfx PPA with:
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
In terminal, run
ubuntu-drivers devices and it should spit out the apt packages that you can try installing, such as
nvidia-settings as well, then reboot.