GDM: users disappeared from login box

Last week my parents’ PC conked out the day before I was due to leave the country, so in the few hours I had to try and knock up a solution, I set up a very old second machine in the house running openSUSE 11.3 with XFCE. I’d previously replaced the default login display manager with GDM, which evidently has various bugs. Aside from the cursor continually spinning around showing as busy, when I added a new user account for my parents, the login box showed two entries under my own name. It’s only on hovering the mouse over the latter entry that my parents’ username shows up. Anyway, I had to explain this and a million other quirks to them in a rush, but the system was all working and they managed to get me an email from it the following day.

Since then, however, when they reach the login screen they say there is just an image of a computer monitor, with the OS version and domain, but no usernames to choose from or other options anywhere, and hence they can find no way to login. I have no remote access to the machine and can only talk over the phone. I suggested a few key combos to see if anything happened, and they booted once in failsafe mode, but no luck.

What could have happened? Is there a key that would show the users again? Perhaps there’s a way to get to a console login, but could they get back to a GUI easily after that? Unfortunately my parents are really not adept at these things and every instruction I give has to be repeated endlessly after which they usually get it wrong a couple of times first, so trying to do anything administrative or more clever than a few key presses or mouse clicks is going to be nigh on impossible. Running a live CD would be likely out of the question since they’d need to change the BIOS boot order first.

They rebooted and were show only the failsafe choice? Usually a reboot will boot to the grub menu and automatically boot the default OS.
There are some sessions options along the bottom of the login screen which might have accidently changed how the screen is shown.
Otherwise you’ll need to call someone close to you who would be able to assist your parents. lso try the browsing the GDM wiki

Also, try GDM wiki:
GnomeDesktopFAQs < CSDocs < TWiki

No they get the normal boot menu which defaults to the standard mode after a few seconds. I just told them to try failsafe mode one time.

I’ve had a long and excruciating call with the folks and finally got them logged in again through a combination of trial, error and sheer luck. I’m worried that whatever caused the issue might happen again though, so perhaps somebody could throw some light on the following:

I got them to do a Ctrl-Alt-F1, login at a console and type ‘startxfce4’, which they say produced this output:

Creating new authority file /home/abcde/.Xauthority
Fatal server error: server is already active for display0. If this is no longer running, remove /tmp/.X0-lock and start again.

(the above ‘display0’ and ‘X0-lock’ might contain different characters to what I’ve typed)

After an ineffective switch to Ctrl-Alt-F7 and back to F1 again, I then took the chance of having them log in as root and typing ‘shutdown -r now’, after which they got back to the GDM login, but with the usernames showing this time. So does that shed any light on why how they got locked out in the first place? I’m pretty sure they wouldn’t have changed any of those options on the login screen because I told them not to touch anything they didn’t understand.

Okay, just found an answer for this elsewhere:

The message about removing /tmp/.X0-lock and starting again - that is a stale socket as root deleted the user socket from temp. This happens when for some reason some one closed xorg wrong and the /tmp/usrname-socket is left active. During reboot it is not deleted so you try to log in and xorg thinks you are already logged in. Very common when putting GDM on your system and the scripts did not delete the socket.

Think I’m going to send them instructions to set up auto-login. Should probably have done it myself before leaving. Will hopefully lessen the likelihood of this scenario occurring again.

Great idea for non-tech users, a lesson learned. Auto-login for non-techs single user works. Pretty sure its not going to matter if they only use one login id.

Good news they’ve gotten

My guess is they shutdown with power or lost power and the correct shutdown was not done. On the other hand did they ever log into the GUI as root?