Cannot read property Collation.This property is not available on SQL Server 7.0
I ran into this today. I tried to connect to a SQL Server 2014 instance while using SQL Server Management Studio 2008 R2. This is exactly the same error I got:


  Cannot read property Collation.This property is not available on SQL Server 7.0. (Microsoft.SqlServer.Smo).


Installing SSMS 2014 did the trick; I can connect and add users fine.