After my display enters sleep mode my system will not awake the display properly. When I press a key to awake the display, the display powers on, but there is no image. Everything works fine until the system enters display sleep mode. My current solution is to disable display sleep in energy saver so the system doesn't crash and manually turn off my monitor when I'm away from my computer. I didn't have this issue with 10.11, so it seems to have something to do with Sierra. I've tried...
Display won't wake after sleep mode
Display won't wake after sleep mode