Hi, I have just restarted the computer and now I cannot log in. I type my psw, than the black screen appears - gray screen and than again the login screen. Could this be caused by low disk space (I have restarted to kill some trash folders, because I was running low disk space). How to debug?
restart your system in Recovery mode, it will drop to a root shell, find how much disk space you have, delete files, then type
exit, it should reboot.
How do I restart in Recovery mode. I am following this guideline and it doesnt work.
reboot system, hold shift or ESC key so that you get the GRUB menu.
The second line should say (kernel info ... Recovery mode)
Thats what I am doing, but it does not bring me to GRUB. It loads Ubuntu MATE green login screen.
So yes, thanks for the help. The problem was caused by not having enough disk space. I would just point out that holding SHIFT on BIOS doesn't work and you have to press it often to be able to reach GRUB. And sometimes, you are not successful, so you have to repeat that procedure multiple times until you reach GRUB.