Here's the error that just popped up as my sync operation finished (5 hours and 30 minutes):

Syncronise failed while writing player configuration.
An operation was attempted on something that is not a socket. (error 0x80072736)

It skipped a lot of the steps in the details list. I power cycled the player, relaunched emplode and it seemed to re-read the database properly and the correct number of songs are now online.

If this is the known cosmetic bug, please ignore.

Bruno