[sql] Set database from SINGLE USER mode to MULTI USER

You couldn't do that becouse database in single mode. Above all right but you should know that: when you opened the sql management studio it doesn't know any user on the database but when you click the database it consider you the single user and your command not working. Just do that: Close management studio and re open it. new query window without selecting any database write the command script.

USE [master];
GO
ALTER DATABASE [tuncayoto] SET MULTI_USER WITH NO_WAIT;
GO 

make f5 wolla everything ok !