Greetings!

How long is it locking for and how big are your drives? Emplode will do the same fsck on the drives, and it will look locked while this is happening. For big drives, this can be on the order of an hour and a half (dual 60s).

As to working for a few days / hours - something is wrong. Usually, there is a counter that will tell how many mounts were done on the drives. When that number reaches a threshold (I think 30), it will force a check on sync.

Are you leaving the drives open in read/write mode? Something is marking the drives as dirty if you see the problem that soon after a sync.