We duplicate the displays on 400 PCs in our environment to projectors. At times when exiting a full screen presentation, it triggers from 'duplicated' to 'show only on 1.' Since the projector is 1 in our case, this means the monitor goes black while the image stays at the projector. I can force it to happen leaving a full screen, but it can also happen randomly. It can happen in any driver version, with any type of cabling. Any ideas on why this is happening, and how to resolve it?