sudo touch /forcefsck
to set my Pi to run a fsck at boot, but it failed with this message:
"An automatic check (fsck) of the root filesystem failed. A manual fsck must be performed, then the system restarted. The fsck should be performed in maintenance mode with the root filesystem mounted in read-only mode"
I ran sudo fsck /dev/mmcblk0p2 – there was a couple of errors that required a ‘y’ to fix, and then it completed. Rebooted, and back to normal. Similar discussion on this message here.