After installing Visual Studio 2010 Service Pack 1, the IntelliSense in SQL Server 2008 R2 Management Studio stops working (most of the time).
The fix is to install SQL Server 2008 R2 Service Pack 1.
The fix for this issue was first released in Cumulative Update 7. For more information on Cumulative Update 7 click here.
Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 R2 fix release. I recommend installing SQL Server 2008 R2 Service Pack 1 or Service Pack 3.
I hope this was informative. Please feel free to leave comments, if any.