How to detect external VGA display on retina MBP running Sierra? I have a 15in Macbook Pro (Late 2013 model) which, until recently, had no problem detecting a VGA projector connected via an adaptor connected to either of the Thunderbolt ports. Today I tried it and it simply could not detect the projector display. The only difference I can think of is that I've upgraded to macOS Sierra since last I remember using this system.

I've tried some other combinations to see if I could figure out what the root cause is, but all of the following options work as expected:


connect an HDMI display to the HDMI port
connect an HDMI display to a Thunderbolt port via an adaptor
boot into Windows 10 (using Bootcamp) and connect the same VGA projector to a Thunderbolt port via the same adaptor


All this suggests it's not a problem with the adaptor, with macOS Sierra using external displays, or with the Thunderbolt ports - just with Sierra driving a VGA display.

Does anyone have any idea what the problem is and how I can fix it?

Edit: I've tried resetting the NVRAM/PRAM settings and I've clicked "Detect Displays" a few times in Display Prefs - no success.
Resetting MBP with display plugged in will detect it, they had the same issue with El Capitan as well. Hopefully Apple will fix this bug.