Since upgrading to Mavericks I have been getting an intermittent issue when trying to do video chat from messages (using my gmail account). I will try to start the video chat and I will get an error message that another application is using the camera. The thing is, I don't use any other applications that would be using the camera. Additionally if I run another app that can use the camera, the camera works fine. if I kill and re-start messages then the camera seems to work. Does anyone have any thoughts on this?