Just updated my iMac to Yosemite and a user has completely disappeared! The account was called Guest (but wasn't a "Guest user") so maybe that has something to do with it. Whatever happened, I've lost a load of important files. Fortunately I have a TM backup from yesterday but before I downgrade and wait god knows how long for it to restore from my NAS, does anyone have any ideas? If I could locate the specific files I'd just add a new user. Thanks in advance.