>Who i could ask to my user to confirm if he want to close the active form when he click on the close control (upper left x).
>
>In which metod i have to put the code
>
>Destroy
>Release
>
>I'm using modal form as a desktop.
>
>Thanks

In the form's QueryUnload, add your prompt to the user (using MESSAGEBOX() I assume). If the user indicates that they don't want to close the form, issue: NODEFAULT and RETURN .F.