Fixing a crushing Light Display Greeter other than the service
Boot from Live USB
mount root partition
$ mount /dev/sda3 /mnt
Enter a chroot to the root directory, here in / mounted as /mnt
$ arch-chroot /mnt
Then execute this command
$ nano /etc/lightdm/lightdm.conf
Toggle the available greeters, this is to fix situations where one greeter crushes such that you can’t login to the system.
Gtk-greeter bit more stable than the other, but lacks major functionalities seen in the others like webkit2 and patheon.
1. Available Greeters
$ ls -1 /usr/share/xgreeters
2. Gnome GTK
greeter-session=lightdm-gtk-greeter
user-session=gnome
3. WebKit2
greeter-session=lightdm-webkit2-greeter
user-session=webkit2
4. Cinnamon
greeter-session=lightdm-gtk-greeter
user-session=cinnamon-session-cinnamon