Reset GDM to default Display Manager

Question

I'm currently running Xubuntu 10.04 LTS and wanted to try out the SLiM display manager on my system.

Well I installed it (from the synaptic package manager) and something really bad happened; I can't even get to the display manage anymore to log in.

When I boot up normally, it shows the Xubuntu logo, then shows this one underscore in the top-left corner of my screen. I tried pressing "Alt+Ctrl+F1" to launch a virtual terminal but that didn't work.

I also tried to boot into recovery mode via GRUB. When I got to the recovery screen, if I were to press any of the arrow keys, the screen would show the Xubuntu logo. If I press the arrow key again, it would go back to the recovery screen, but it wouldn't move down an option.

It isn't too bad if I'll need to re-install Xubuntu (I backed up all my important data a day ago), but it would be a real pain in the but if I had to.

Any help is appreciated. Thanks!

EDIT: I forgot to mention that maybe resetting GDM to the default WM might fix it, but you see, I can't even log in to try to edit the "/etc/X11/default-display-manager" file.

EDIT2; I decided just to bite the bullet and re-install/update Xubuntu. Thanks for the help though.

Answer 1

You can use a text-based virtual console to perform configuration changes. Press Ctrl+Alt+F1, then log in. You won't see any *s or anything at all while entering your password. That is by design.

You can then remove slim via the command line, which will reconfigure your other display manager to work again (since you didn't actually remove it). This command will do that:

sudo apt-get remove slim

Or you can reconfigure your other display manager (in this case, gdm) to be the default, while keeping slim installed:

sudo dpkg-reconfigure gdm

(Thanks to Anwar Shah for pointing this out.)

As another alternative, which does not require rebooting, you can manually stop slim and start your other display manager (presumably gdm on this system). slim may well be stopped already, but issuing the stop command will then simply fail, and will not be harmful.

sudo stop slim
sudo start gdm

On later systems, you may have lightdm instead of gdm as the default display manager. Then you'd use sudo start lightdm instead. Similarly, on KDE, you may have kdm, so you'd use sudo start kdm instead.

You've asked how to revert to gdm. If you want to try to fix slim so it works properly, you might want to post another, separate question about that.

Finally, a note on terminology: these are display managers, not window managers.