Sync stops working

Although I was initially successful in syncing databases between my desktop (iMac) and laptop (MacBook Retina Pro), sync stopped working, or rather it gets stalled in an endless loop in which it constantly returns the growl message “Lockfile updated.”

Both machines have DT Pro Office running in 32-bit mode; I’ve reinstalled the sync plugin on both machines; and I’ve copied the databases from one machine to another using a portable hard drive.

All to no avail.