I am currently using Ubuntu 18.04.3 LTS, and I randomly got a login loop upon restarting my PC. The content of my /var/log/lightdm/lightdm.log is the following:

Greeter connected version 1.27.0 api=1 resettable=false
Greeter start authentication for malek
Session pid=1767: Started with service 'lightdm', username 'malek'
Session pid=1767: Got 1 message(s) from PAM
Prompt greeter with 1 message(s)
Seat seat0 changes active session to
Seat seat0 changes active session to 4

I did select the save session on restart option, which I only started doing two days ago, and I never had to encounter this problem before. My home directory and all of the files inside of it belong to malek

I am completely stumped, I don't want to re-install Linux (unless there's a way to do so without loosing your users)

Thank you for you help.

2 Answers 2


Please do the following as mentioned here.

Did you end up here after running sudo startx? Nevertheless:

Press Ctrl+Alt+F3 and login into the shell.

Now run ls -lA. If you see the line

-rw-------  1 root root   53 Nov 29 10:19 .Xauthority

then you need to do chown username:username .Xauthority and try logging in (you may also need to do the same for for .ICEauthority).

Else, do ls -ld /tmp. Check for the first 10 letters in the left: they should read exactly so: drwxrwxrwt.

drwxrwxrwt 15 root root 4096 Nov 30 04:17 /tmp

Else, you need to do sudo chmod a+wt /tmp and check again.

If not both, I'd recommend you either

  1. sudo dpkg-reconfigure lightdm
  2. or uninstall, reinstall it.

Now press Alt+ until you reach the login screen again, and restart.


sudo chown username:username .ICEauthority solved the issue for me.

It read as -rw------- 1 root root using ls -lA, and chown returned ownership to my user.

The problem was likely caused by my attempt to install x11vnc for X11 forwarding; it must have modified permissions for that file, which caused the bootloop.

Uninstalling x11vnc and sudo apt-autoremove did not fix the issue.

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