cannot switch user from admin user

[kopolov]

Ubuntu 11.10

I have 4 users defined.
One of the users has the admin privileges (able to sudo) and the rest are regular users.
When logging in from a regular user, I am able to switch to a different user.
When logging in from the admin user, after clicking the "switch user", the screen goes black (as if in screen saver) and then when I move the mouse, the screen returns to a "lock screen" screen (where I need to put the password for the admin user). If I try then to press the "switch user" button, the same things happens.

After entering the password, I see a pop up window on the desktop:
"Failed to unlock: The name org.gnome.DisplayManager was not provided by any .service files"

The only way to login as a different user is first log out as the admin, then login as a different user.

I tried the following:
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get --reinstall install ubuntu-desktop

but the problem persists.
Please let me know what other data you require and I'll attach it.

Here are some more details:
hagai@BRUCE:~$ lsb_release -rd
Description: Ubuntu 11.10
Release: 11.10

Hagai

[kopolov (kopolov)]

I am not sure its lightdm since I'm using gdm.
I switched from lightdm to gdm due to some problems I had with lightdm.

Hagai

[kopolov (kopolov)]

or maybe not.
I did:

hagai@BRUCE:~$ cat /etc/X11/default-display-manager
/usr/sbin/lightdm

Please ignore my post.

Hagai

[Robert Ancell (robert-ancell)]

Could you attach /var/log/lightdm/lightdm.log after this occurs? Thanks.

[kopolov (kopolov)]

Here is the log file

[Robert Ancell (robert-ancell)]

What desktop is the admin user running? The lightdm log shows no request to it to switch users.

[Launchpad Janitor (janitor)]

[Expired for lightdm (Ubuntu) because there has been no activity for 60 days.]