A number of Mac users in an Apple Support Communities thread are reporting that Apple’s 10.9.2 update to Mavericks has broken AirPlay Mirroring to Apple TV and the ability to extend desktops to external monitors.

I just updated to 10.9.2 and now when i try and airplay mirror to my Apple TV, it sends the audio but just shows a black screen and i can’t drag anything to it. It doesn’t show any of the options for external displays in the displays section of System Preferences …  expand full story