Hello all, I recently got a new raspberry pi 2 and installed retro-pie on it.  Having used most other versions of retropie, I quickly had 7 systems set up with at least 100 games each.  Upon rebooting the pi after the splashscreen went away the command read FAILED in red fallowed by some text i couldn’t read, and rebooted the system.  After the pi rebooted entire sets of roms were gone, all of NES, SNES, Genisis.  Brushing it off as a glitch I recopied the roms and upon another reboot, Genesis, Atari, and mame.  The roms are in alphabetical folders called A-G, H-R, and S-Z respectively. 
The question is why are my games being deleted by retro pie 3, it is really disappointing to have to reinstall most my roms upon a reboot.