Maybe it's not the social control -- the one that hold activities and notes.
Anyway, when an Account is opened I get a System.NullReferenceException (message in the downloaded ErrorDetails.) Then when I change the Activities view to "In Progress" or "Overdue" it is fine, but upon changing it back to "All" the error pops again.
A little more background: This instance was just raised by importing a 2011 instance database in the deployment manager -- the Microsoft preferred method for upgrading.
Is there some known solution?