I am trying to add a SQL Server data source to a C# console app.
When I try and add a new connection to my .dbml file the only Data Source available is Microsoft SQL Server Database File (sqlclient) whereas I need Microsoft SQL Server (sqlclient).
The change button is grayed out, so I can’t change it.

How do I change this?
(I wondered if it was a bug, so tried uninstalling/reinstalling Visual Studio – but still no joy.)
This is actually a limitation of the Express product and you can get around it with a modification of your SQL Server connection string manually. For more information have a look at this SO Post.