
my HP monitor needs to be connected via mDP + HDMI). It now seems an HDMI device needs to be continually present for everything to work reliably (i.e. However, I've subsequently discovered I can't reproduce this configuration. This all worked perfectly! I then wondered whether I needed a monitor plugged into the HDMI dongle at all so I unplugged the cable and found that everything still worked! That's when I wrote the above comment. While playing around trying to get the 'virtual' monitor configuration to work, I connected an HDMI cable between the HDMI dongle and an HDMI port on the HP monitor (so I effectively have two video inputs into the same monitor). The dongle I used is a Cable Matters Display Link USB to HDMI adaptor. I use the mini-Display Port on the Mac for this output. I've got an external HP monitor that I use with my MacBook Pro for the live OBS program output (stands in for the projector when I'm doing testing). I need to revise my description somewhat, based on what I've discovered after some more experimentation! Sorry - I meant to put the link in my message, but forgot.
