All of my Ubuntu 18.04 LTS installations eventually gets stuck in a loop where the screen shows the last user who logged in and is prompting for a password.

It has the following options:

Cancel, Unlock, Log in as another user, and Entering the password.

The user can't enter the password because he doesn't know the other user's password. The power button at the top right only has the option to put the machine to sleep. It doesn't have the option to reboot.

I'm aware that someone can use the Ctrl+Alt+F# hotkey to switch consoles. However, this has many people locked out of the computer unless they perform a hard reboot.

Does anyone know what can be done to stop this loop from happening?

  • What happens if you press Cancel? – Soren A Apr 18 '19 at 16:48
  • It will go to the screen that has the time displayed that has up indicators showing how to get to the login screen. When you scroll up to login, you're back in the loop prompting you for the last user's password. – L. D. James Apr 18 '19 at 18:28

I've managed to fix this by disabling Wayland usage in gdm3. Edit /etc/gdm3/custom.conf, replace




and restart everything.

| improve this answer | |
  • Thanks I'll give it a try. By the way, it doesn't happen all the time. Some times it goes weeks without happening. It's been happening off and on, on various computers since the initial release of 18.04. If it goes a couple of weeks without happening to any of the computers I'll update this thread. – L. D. James May 18 '19 at 19:59
  • 1
    Your answer cures the problem perfectly. I'll research later to see what benefit is built into Wayland. I tried to stick with a vanilla install to be able to help with support of others. But of course, the Linux experience over man other OSes is about being able to have your personal Desktop experience... and still be in compliance. It's not a one size fits all. Thanks! – L. D. James Jun 1 '19 at 14:44

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