Your home directory is listed as /home/andy but does not appear to exist
Rooting around on the internet came up with the same problem, but no answers that worked. Booted into terminal (Ctrl+alt+F1) and found via LS that /home was either non-existent or empty. This got me thinking, have I done something inadvertently that has screwed up /etc/fstab. Background - I've got root in one partition and /home in another partition in my SSD. Booted again from the REDO drive and sure enough, no entry in fstab for /home.
Thank god for backups - I back up daily using rsync to a 256GB SD card in an expresscard slot and more infrequently using REDO to a USB drive for partition images. All I had to do was go and copy fstab on the SD card back into /etc, reboot and everthing worked!
Sounds simple, no, it's been a stressful three hours figuring this all out - so a lesson to others, and if you get the same error then this might be what went wrong (from looking on the web there are other ways to screw up your systen and get the same result).
How I came to mess up fstab in the first place - I have absolutely no idea, but I had been messing around with the partitions on the USB drive.
Whatever you do, do backups.