Hello,
When I taught at school before coronavirus, I used to plug an HDMI cable into my laptop, and the machine in the classroom would share my laptop's screen image through the projector. Now, almost two years later, when I tried to do that again, the projector showed only an empty blue screen.
I tried a colleague's laptop, and the projector worked fine with that other laptop. I tried my laptop again, and it still didn't work. Just the blue screen. We tried switching projector inputs. We tried rebooting both laptop and projector in various orders. We tried uninstalling and reinstalling my video driver. Nothing worked. But my colleague's laptop worked fine.
I think my HDMI output is functional. When I enter Settings on my laptop (Start -> Settings -> System -> Display) while the HDMI cable is connected, I get a blue rectangle on the Display settings page that has a "1/2" displayed on it. When the cable is unplugged, that disappears. Also, only when the HDMI cable is plugged in, I have additional options on the Display settings page, about what to do with the second display, such as mirror the primary display. Those options disappear when the cable is unplugged.
Thus, I wonder, are there any settings in the operating system that would disable the HDMI output? A few weeks ago, I changed a number of settings in Settings -> Privacy to disable unnecessary reporting to Microsoft and to disable unnecessary sharing of system resources with apps. Perhaps one of those settings also disables screen sharing over HDMI? I've looked through them and tried changing back quite a few, but nothing is helping so far.
I would greatly appreciate any help that you can offer!
Sincerely,
Eric
