Boot error

Hi everyone
LEAP 15.1 has been running OK for a month or so.
This morning however the boot process stops with this message

Give root password for maintenance
(or press Control-D to continue):

If I give the root password, it logs in the terminal and nothing more.
Control-D has no effect.
Any suggestions?
Thanks in advance

Control-D produces this output


sulogin: cannot read /dev/tty1: Operation not permitted
You are in emergency mode. After logging in, type journalctl -xb to view system logs etc.

You could start hitting Esc during boot to see what happens immediatly before it stops.

Some of the filesystems defined in /etc/fstab failed to mount. Check what you have there, or post content.

I have no idea how you deduced that from the error message. However I removed the last line

/dev/sdb1 ...

from the fstab file and now it boots as before. Pretty sure I didn’t edit this file yesterday nor in the days before though.
Many thanks.

This is so far the only reason systemd enters emergency mode.