My username is deleted from the list of users at login screen. I am entering the right username and password and I can’t login. Also can’t login through tty. Solution?
Hello @antoniotr 
Just recreate the user as root:
useradd username
However, if you did not set a password for root before, then you can’t login. Only way is now booting into a live session, chroot and create a user there and set a password:
useradd username
passwd username