FYI...
I copied over about 70GB of music in one shot the other day using the "Sync" feature to my hacked VW Phatnoise DMS. I noticed that I was getting an error that would produce a dialog box asking me "yes or no". I forgot what the error/question was. Anyways, it would halt the copy process and it kept repeating being problematic.
I noticed that if I clicked the “Cancel All DMS File Transfers” button in the bottom right corner and left the confirmation dialog box open, the copying would proceed uninterrupted.