I updated to Beta 2 last week and all of a sudden FaceTime, Photo Booth, and QuickTime cannot find the inboard camera. However, the system profiler shows a FaceTime camera configured. I thought perhaps it was an application I had installed, as I installed several, so I reinstalled a copy of Beta 2 and low and behold the camera and FaceTime worked. I reinstalled apps and it stopped working. I did the Beta 2 install once more and found that it wasn't the apps causing the issue, as FaceTime worked fine with a ***** copy of Beta 2, until the Mac went to sleep/hibernate, at that time it would never work again until reinstalling Beta 2 again, and then it would repeat the same behavior, working at first then stopping after X amount of time passed. Very frustrating as there is no way to use FaceTime, Slack, Hipchat, Photo Booth, or Quicktime with Beta 2.
I also tried all of the SMC, NVRAM, process kill solutions out there to no avail.