Dell Latitude Connected to a Projector Doesn't Project My Laptop Screen
Re: Dells not displaying correctly to projector
There are several layers of "settings" between the laptop and the projector.
Firstly, the FN+F8 keys need to be pressed for the laptop and the projector to "detect" each other. Sometimes you need to press these keys together twice to toggle to the right mode. If this doesn't result in a cloned display, it results in an extended display (where you can see the desktop background on the projector but not the actual windows/icons). As you have discovered, to switch from an extended display to a cloned display, you need to use the Nvidia control panel. If you've gotten this far, and you get the desktop background projected but the "clone" setting doesn't stick, it's possible that the driver/the nvidia software need to be updated. Ideally we would try doing these updates on one of the problematic laptops, see what works, develop a documented procedure and repeat it on the other ones.