December 18, 2020
We just bought a DisplayPort to HDMI Multi-Monitor Splitter - 3-Port MST Hub from startech.com Connected it to our Macbook Pro, and now WE says that main display is off. Won't even allow us to select a display for the program. We did have a Displayport that converted to vga for a projector, and it found that one just fine, but now it isn't detecting. Not sure what happened between moving from a singular to a multiple monitor output that would cause WE to stop recognizing output options.
December 18, 2020
Does macOS see the display?
December 18, 2020
Yes it did. We connected other displays to it, but I believe it wasn't extended display it was same as laptop screen.
December 18, 2020
You'll want to make sure it's extended and not cloned.