If the application is a third party setup, you will need to contact the vendor for a way to suppress this dialog, as there is no functionality built into Windows Installer to suppress this dialog if the /qn switch will not do it. The reason being that this dialog may not be directly called by the msi, but rather called from a .dll or .exe through a custom action.
If the setup is one of your own, then how are you calling this dialog? If you're calling it from a custom action, then you could always condition this custom action with a property value that you could set at a command line at runtime to determine whether or not it launches.
Hope this helps.
Mark D.
Software Quality Engineer
InstallShield Technical Support
