Sorry for being a nube. I'm using VS2015. Within that framework I'm using SQLExpress. The database I've created as an MDF has the connect listed as Microsoft SQL Server Database File (SqlClient). I wanted to used linqpad to play with LINQ using the MDFs I've created. When using Linqpad 4 or 5 to connect to the MDF, it get the error 26 message, cannot locate server. Am I doing something wrong? Thanks!