I got a successful sync on my big tree this morning - what a shock! The last good sync I had previously was in November 2012 and I have re-downloaded my entire tree several times since then. This morning, it took 45 minutes to get a successful sync (plus media download time) and was worth the wait. I have been keeping track of my counts of Ancestry file and FTM file before and after each sync attempt because of the duplication problems caused by earlier versions and my counts were exactly what they should have been.
I was thrilled to say the least.
However, when I went to sync another small tree this afternoon, I got the "sync error..." message on that tree within 3 minutes.
Came over here to see if anyone else was having success and I see that some of us are.