I think it was a matter of file timestamps, but I cannot be certain. All I know is that by correcting the clock, the syncs went much quicker.

Weird. I'll look into it. AFAICS the decision about whether to check the disk is made based on the timestamp on the filesystem (not the files). As the filesystem is only ever opened or closed by player-side code, I'd have thought the player clock only needs to be consistent, not necessarily correct. But enough people have reported this type of problem that there must be something stranger going on.

Source code: the truth is in there.

Peter