Apple TV stopped working on my iMac after this update. Has anybody experienced this problem?

There are stories of Ethernet cards being deleted/unrecognised after a silent security update titled "Incompatible Kernel Extension Configuration Data: 3.28.1" (see http://forums.macrumors.com/threads/software-update-031-51913-will-break-your-et hernet-driver.1958521/) so this same update may have affected Apple TV connectivity via Wi-Fi as well. It was working fine two weeks ago. I had this update installed on my Mac Mini yesterday at 5:38 PM EST. Today when I try to connect to the Apple TV with AirPlay I get the message 'Could not connect to "Apple TV" '.

Do you get the same message? Are you trying to connect via Ethernet or Wi-FI?

I get same message

Wi-Fi. I can get the menu pages, but not the app page that shows netflix, etc.

It will then go back to page with picture of computer on left and settings on right.