Even after many years you can experience a strange meltdown during an innocent update. In Manjaro during updating, which I always do in the terminal using pacman -Syyu because I want to see the feedback, the post-installation processes like grub updating were going on, when suddenly the login animation of lightdm-plymouth appeared.
Soon was clear that it was stuck in that. Strange was that I noticed no shutdown before that. I was worried that the grubupdate might not have finished and rebooted. Again stuck in the login animation. I use autologin btw. First via Crl+ Alt +F2 I opened a second terminal and did a grub update:#update-grub.
This proved no solution. Most of the time I saw no feedback or error message or so short that I couldn't extract information. Then I recognised in a short flash the word plymouth and found out that that lightdm was using plymouth.
In the second terminal I then tried to start lightdm again and xfce was launched.
After doing some reading I decided to get rid of plymouth and lightdm: I want to know what is going on during the boot process in case of failure.
A very clear write through is
to be found here
Repeating the essentials:
in /etc/default/grub remove word
splash from the line GRUB_CMDLINE_LINUX_DEFAULT.
and in /etc/mkinitcpio.conf
remove word plymouth from the line HOOKS.
Now in XFCE via System kernel you can view your installed kernels and do for instance, according to the kernels you have
#mkinitcpio -p linux54
to rebuild your kernels.
Now we are going to disable lightdm
#systemctl disable lightdm-plymouth
#rm /etc/systemd/system/display-manager.service
Remove plymouth:
#pacman -R plymouth plymouth-theme-manjaro-elegant
Replace lightdm with lxdm (not necessary, but I like lean applications):
#pacman -S lxdm
with the force flag:
#systemctl enable lxdm -f
At last but essential update grub:
#update-grub
