On macOS Sierra Airplay is always "Looking for Apple TV" 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?
I was having the same issue. It started occurring when my external speaker tried automatically connecting to the device. Turning off bluetooth entirely solved the problem for me.