I’m sorry to say that all of a sudden 4.1 stopped properly syncing for me. It would not sync all the playlists. I tried 4.3 as a fresh install on a different computer and it wouldn’t sync at all with my database. (See Vanishing Playlists)
I’ve concluded that some gremlins contaminate the database(s).
My only solution was to switch to Lexicon DJ. It imported my Engine database with no issues. It will write (sync) performance drives as well as write to a standard Engine DJ desktop database. At least in my case, it works fine because all of my music is stored on my desktop hard drive. In fact, now I just prep and manage my music in Lexicon DJ and don’t even use Engine DJ desktop. Of course, I still use Engine as Engine OS is on the players.
Yes, Lexicon DJ is paid software, but, so far for me, it just works and has a lot of nice added features. I found a 20% off coupon that saved me on the year’s subscription.