User account missing after upgrade to Yosemite?

Question

I have a mid-2010 iMac which up until recently I had two user accounts on for general use and one for music (Garageband, Logic and audio files etc). After upgrading to Yosemite, this separate user has vanished. I'm left with my original admin account, and a guest login. If I search for any of the files using spotlight, they do show up, but if I try to open them I get the message "you do not have permission to open this document". Also I had folders on the desktop of the music account which contained files, these folders show up in a search but are listed as empty? The files themselves are 'blank white sheet' icons as if they have no application.
I would assume this is a lost cause if not for the fact that my hard drive (more than half of which was taken up by the 'music' user) still reads as pretty much full up. So have I wiped all this forever?
Thanks in advance,
Dave

Answer 1

retina MacBookPro mid2012. Clean install of OS X Yosemite 10.10
I'm randomly missing an account at login screen after reboot.
Sometimes I can fix it with booting into my initial account 'Kevin' (userid 501) and then changing to different login 'Christina' (userid 502).
But if I log out from my account, the second account is missing. Same if I do a reboot.. This have me in stitches as I ofcause has the need for privacy from each account.
Both accounts are set up as admins, guest is deactivated.
rMBP 16gb sep2012.
userid 501:
home directory: /Users/Kevin
userid 502:
home directory: /Users/Christina
apart from that... I have loads of problems with Bluetooth, and hand-off only working 1 way (5s with 8.1) where only iOS -> OS X works, not vice-versa.