In Visual Studio, when you right click on the App_Data folder and try to add a new SQL Server database, you may receive the following exception:
Connections to SQL Server Files (*.mdf) require SQL Server Express 2005 to function properly. Please verify the installation of the component or download from the URL: http://go.microsoft.com/fwlink/?LinkID=49251.
Connections to SQL Server files (*.mdf) require a SQL Server user instance, which is a feature of SQL Server Express edition and is not supported by other editions of SQL Server (such as Developer or Enterprise).
In general, the exception has the following causes:
- There is no SQL Server Express installed on the machine.
- The SQL Server Express instance is not running.
- Incorrect instance name of SQL Server Express is specified in Visual Studio.
Note: Because SQL Server 2008 is released after Visual Studio 2005 and Visual Studio 2008, the exception message does not include SQL Server 2008 Express.
Verify that SQL Server express edition (either 2005 or 2008 version) is properly installed and is currently running on the system. You can use SQL Server Configuration Manager to check and start the SQL instances that are installed on the system.
If the SQL Server Express instance is running, check if Visual Studio is pointing to the correct SQL instance. You can do this by navigating to Data connections under Tools -> Options in Visual Studio IDE.
Article ID: 2009225 - Last Review: Dec 15, 2009 - Revision: 1