Sudon't
Soooo... I guess I added her profile to the mitch group and vice versa so we can share the music folder BUT I didn't add the right argument ( -a , I think - look it up!) to the usermod command or whatever I used, so the upshot was that I made her group the ONLY group I was in. Effectively, I deleted myself from the sudoers group and all the other default admin and device groups and whatnot. Real pain, because once you're out, you've no way back in - like the opposite of the Mafia. Looking around there are various suggestions but I went for the simplest one (the one I could understand): Used the eOS usb as it was first to hand, to log into a live session. As noted my previous post , I mounted the root file system: > sudo mkdir hdd > mount /dev/sda /mnt/hdd > nano /mnt/hdd/etc/group then I just added my username to the appropriate groups: root:x:0:mitch and adm:x:4:mitch and sudo:x:27:mitch works!