Do a hard reset again to start from fresh after the update.
Your best bet is NOT to restore your back up file for now until you know what program(s) is preventing you from syncing.
Try creating a new partnership and see if you can sync before you do any restoring.
It took me a few hours to realize that after I restored my backup, my MS Entertainment Pack and MS Pocket Steets had old file drivers that were messing up my sync. When I went to reinstall one of these programs, I got a msg if I wanted to replace a new(current) file with an old dated file. Of course I said no. But after I figured it out, nothing has gone wrong since.

It will take a lot of patience but that's the best that I can think of. Sorry but I hope it helps.