"No connected camera" error using MacBook Air I have a friend with a 13" MacBook Air. He upgraded to the new software in the App Store about a week ago and now, when he is using anything that uses his built-in camera, it says "There is no connected camera." I've tried looking through his settings and nothing is working to fix the problem. I've found a number of problems, but nothing has worked. We're not sure how to go about solving the problem, even after finding several solutions to no avail. 
Anything helps, thanks!
Probably there is some process holding the camera. A dirty hack to solve this issue is to kill the culprit with:

sudo killall VDCAssistant