title: Cannot add App_Data SQL Server database
body: <p>Using Visual Studio  2010 10.0.20319.1 RTMRel and SQL Server Express 10.50.1600.1 I'm trying to add a new SQL Server Database .mdf, however, I receive the following error:</p>
  
  <blockquote>
    <p>A network-related or instance-specific
    error occurred while establishing a
    connection to SQL Server. The server
    was not found or was not accessible.
    Verify that the instance name is
    correct and that SQL Server is
    configured to allow remote
    connections. (provider: SQL Network
    Interfaces, error: 25 – Connection
    string is not valid)</p>
  </blockquote>
  
  <p>I have enabled TCP/IP and Named Pipelines, added Firewall Exceptions for Sql Server, I am successfully connecting from VS in the  Server Explorer window.</p>
  
  <p>I would appreciate if someone can pint me to a solution to my problem.</p>
  
  <p>Thank you.</p>