I had some total wierdnesses happen with the original release. A tree that sync'd perfectly during beta testing was suddenly totally f----d up with the production version. I gave up on it until the 1st patch was released and that SEEMS to have fixed the problem I was having.
I'm running on Vista with 32-bit Home Premium and I believe what I was experiencing was system specific at that time.
I don't rely on my Ancestry tree as my main database and don't have any guests invited so restoring it is a royal pain but not the end of the world. I also have only a couple of hundred media records attached. Tree size is about 4700 people.
I really feel for you.