Center the login screen on Ubuntu 23.10

Question

Since I got my Ubuntu 23.10 installed the login screen text box stays on the left, whereas I believe it should be in the center of the screen. Here is a picture of my login screen:

I don't know if this is normal but any help with this would be amazing.

Answer 1

You are most likely using LightDM (lightdm package) as your login manager (as @Daniel T said) instead of the default GDM (gdm3 package). I suppose that you ended up with LightDM either because you didn't do a clean install, rather you upgraded from another installation where you had lightdm installed, or because you followed some guide to configure your system and you installed lightdm without noticing.

To remove lightdm and replace it with gdm3 run the following commands in a terminal:

sudo apt install gdm3
sudo dpkg-reconfigure gdm3
systemctl stop lightdm
sudo apt remove lightdm
systemctl start gdm3

• Reference: @Sophia Marie's answer in How do I switch from LightDM to GDM?

Answer 2

You should not see that outdated lightdm login screen. Let's make sure you're using the new gdm3 login manager, which is also needed for your lock screen to work:

1. Install the correct login screen and desktop:

   sudo apt install gdm3 ubuntu-desktop
   

2. Remove all other providers of x-display-manager:

   sudo apt purge xdm wdm slim sddm nodm lxdm lightdm greetd
   

3. When lightdm is removed, you might see a dialog in the terminal asking you to select the display manager. Select gdm3.

4. Reboot.

I only remember seeing lightdm 10 years ago. See @BeastOfCaerbannog's answer for how this could have happened to you.