I practiced my PowerPoint (Windows in VM) presentation at home, using an external HDMI TV set. Every time I plugged in the TV, the "Are you going to show a presentation?" message appeared, I clicked Yes, and PowerPoint worked just as I wanted, showing just the slides on the TV, and the slides plus my notes on my Macbook Pro screen. When I got to the venue to actually deliver my presentation, I plugged in the display in the meeting room (also HDMI), and the "Are you going to show a presentation?" message did not appear. The room's display worked fine; my MBP's screen appeared on it right away. I tried unplugging the external display, restarting my MBP, and re-plugging the external display many times; each time the "Are you going to show a presentation?" message did not appear. I was forced to give my presentation without my notes. Is there a way to force the presentation message to appear when it does not automatically pop up? Some key combo, perhaps? I found nothing in the manual.