Please correct me if I'm wrong. But the "RebootYesNo" is a private property, that doesn't affect the installation. I know it is "Yes" by default, but all of my msi's have that even if they don't reboot. "REBOOT" is a public property, so no need to edit the msi directly because public properties can be manipulated though commandline. Also, I don't know why reboot=reallysuppress didin't work when I tried it. Only reboot=suppress works for me. Tip: All UPPERCASE properties, are public properties. You can modify them though commandline. All lowecase properties (or properties with alternating cases) are private properties. You cannot modify them easily. I believe it is useless to edit a private property.