We are Synchronizing successfully for some months now. Since 3 days ago, the synchronisation takes forever. meaning, we waitet up to 24 hours with the sync but it wouldnt complete. There are no big attachment and no special changes were made.
When something like this just mysteriously starts happening, the first thing I think of is Windows Update. Were any updates applied around the time this started? Have you tried removing any Windows Updates from around that time, as suggested in this thread?