I´m a noobie so please be patient ! I developed an app using C# and SQL Server Express 2012 with a local database, my connection string is"Data Source=localhost ; Initial Catalog = scalnet ; Integrated Security=SSPI; Trusted_Connection=Yes"; Everything worked ok till the time I made a setup and tried to install my app in another computer. My first question is: - What version of SQL should I install is this machine? it should be as ligth as possible. - I tried to install SQL exprees 2012 but it gives me an error when I execute my app "A network related or instance specific error occurred while establishing a ..... (provider:Named Pipes Provider, error:40 - Could not open a connection to SQL server." This probably should be a problem with the server configuration but I have no ideia how to solve this... Can anyone point me to the rigth direction ? ? Thanks