Can't login with LightDM 11.10

Hi, maybe it's a bug and I suggest to you to add a comment on this bug:
https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/873368

Or search for other bug that looks like your problem.

Alternative, verify if lightdm-gtk-greeter and unity-greeter are installed.
Verify
/etc/X11/default-display-manager
points to
/usr/sbin/lightdm

Try:
sudo stop lightdm
sudo dpkg-reconfigure lightdm
sudo restart lightdm

Maybe ~/.Xauthority owned by root?
Bug #871667

@sam, thanks for mentioning the xauthority bug, that helped me while looking for a solution for the same problem

Hi.

I can´t login with lightdm and with gdm either. I remove .Xauthority, i had changed sudo and user passwd, install, reinstall, reconfigure, update, upgrade, .... i am going to reinstall all again.... oh, no, please help, windows returns in my head.... oh, no....

If its not .Xauthority or lightdm problem then it might be /tmp permissions problem.

Open the file /var/log/auth.log and search for gnome-keyring-daemon.

If you find lines similar to these:

Jan 18 01:55:12 localhost gnome-keyring-daemon[2016]: couldn't create socket directory: Permission denied Jan 18 01:55:12 localhost gnome-keyring-daemon[2016]: couldn't bind to control socket: /tmp/keyring-mKRg6t/control: No such file or directory Jan 18 01:55:12 localhost lightdm: pam_unix(lightdm:session): session closed for user

then the problem is that you probably changed the permissions of directory /tmp by mistake.
So now the users dont have permission to write inside the /tmp directory and this is why you loopback to the login screen of light destop manager (lightdm).

You can still probably login as root and give this command
chmod o+t,ugo+rw /tmp
or
sudo chmod o+t,ugo+rw /tmp (if you are logged as user through a terminal)

This command sets the correct permissions (drwxrwxrwt) for /tmp directory and then you can login again normally.