EntityFramework - Cannot attach the file as database
In one of the project I was using LocalDB and EntityFramework's Code First approach.
I manually deleted files from App_Data folder, and the next time I started the application or tried to execute update-database command, I got an error message saying 'Cannot attach the file NNN as database NNN'.
To fix the error, open the Package Manager Console in Visual Studio and run the following commands:
sqllocaldb.exe stop v11.0
sqllocaldb.exe delete v11.0