I am currently in college. Yesterday, August 19th, every Mac on campus could not hear any audio. I mean ANYTHING. We could control our volume still, but no noises could be heard. Online videos stopped working as well. Through trial and error, we narrowed it down to the Wifi. When we turned wifi off, sound would work again. When we turned it on, everything went away. We then found out that it specifically deals with AirPlay. Airplay is causing the issue somehow. And this is huge because it affected EVERY Apple computer on campus. We have tried commands to disable apple mirroring, commands to reload audio and video, PRAM and SRAM resets, etc. Nothing is working. We need help.