Basically, the reboot is a Windows Installer property, not a switch. So, wherever you have an MSI setup, the correct way to reject a reboot is REBOOT=Suppress (note that there was no "/" preceding it). Moreover, some installers want the property to be all capitals, which is why I have it that way above ("REBOOT" and not "Reboot"). Also, some I've seen some setups needing REBOOT=ReallySuppress (that switch to reject a reboot, instead of the one to simply "suppress" above)