RA Library Server Required softwares Visual Studio 2013 Update 2 and above .Net Framework 4.5.1 Microsoft ASP.NET Web API 2.2 5.2.3 EntityFramework 6.1.3 Microsoft SQL Server 2012 FAQ It shows *"Cannot attach the file .mdf as database" error. Open SQL Server Object Explorer Click refresh button. Expand (localdb)\MSSQLLocalDB(SQL Server 12.x.xxxxx - xxxxx\xxxx) Expand Database Please remove existed same name database Click right button and then delete Go back to your Package Manage Console Update-Database