Just upgraded to macOS 10.12.1 Sierra and the mirroring display options keeps oscillating between: "Looking for Apple TV" and "Off".
In preferences i have turned AirPlay Off. But it keeps looking for AppleTV. As recommended in an earlier discussion i tried:
sudo chmod 000 /System/Library/CoreServices/AirPlayUIAgent.app/Contents/MacOS/AirPlayUIAgent
but it gave an error:
chmod: Unable to change file mode on AirPlayUIAgent: Operation not permitted
It looks like Sierra always wants to keep connecting to Apple TV - big nuisance. Any other ideas to turn this auto feature off?