i think it's a bug with graphic driver nvidia/ati..., i had this problem after a security update of this driver. i removed this driver, reboot my pc and i could login. after that i installed my graphic driver again
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1628790 Title: Changing the user settings to autologin on Lubuntu 16.04 causes LightDM to get stuck in a login loop Status in lightdm package in Ubuntu: Incomplete Bug description: After setting my account to login automatically through the user and groups setting in Lubuntu. After the computer reboots it gets stuck in a loop on the login screen. Logging in will just send you back to the same screen. The only way I could fix the issue was to press CRTL + ALT + F1, logging in through the CLI and typing: "sudo mv .Xauthority .Xauthority.bak" and then once I was back to the login screen I was able to login and turn the setting off. I did check to see weather that was what caused it, by restarting the computer without turning off the auto-login. However the same issue happened and only turning off auto-login would stop the login loop. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1628790/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
