VisorCentral.com (http://discussion.visorcentral.com/vcforum/index.php)
- How To / Troubleshooting (http://discussion.visorcentral.com/vcforum/forumdisplay.php?forumid=2)
-- One reason for hotsync failure (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=2080)

It seems as though hitting the hotsync button while a DateBook+ (dunno about original Datebook) alarm is up causes the hotsync function to stall until a software reset.

So before doing a hotsync, turn on your Visor and ensure there are no alarms popped up first.

This has happened twice to me with the same result.