Recently, Microsoft has released the August Cumulative Update for SharePoint 2010.
I have to say don’t install it (at least for the moment).
Indeed, this CU make the synchronization service not working, if you have already it configured and running.
Microsoft Support was able to reproduce it, and was also able to say ‘if I delete the existing profile service and recreate a new one, everything is working fine’.
Another thing, is the search is no more returning document in the results page; only site and page.
So, don’t install the August CU if you have already your SharePoint 2010 farm up and running.