and now the unit hangs at Rebuilding Music Databases upon boot for nearly a minute before continuing and playing music.

You'll keep getting this after every reboot until emplode is able to rebuild your database. The player seems to be walking the entire contents each time you boot, and obviously isn't writing back to the disks. I had the same problem after one of my syncs aborted early.

Of course rebooting the PC and connecting up again allowed proper syncing right away.

Bruno