I can't give a specific reason but when I boot my mac pro from a clone, I can lose my usb webcam (hp 920). The only way I can get it back is to reset the SMC. It stays fine if I reboot to the same drive each time but changing volumes is doing something weird.
If you do reset the smc, select your boot drive again from system prefs.
iso250 wrote: ... last year I started to find that when I Facetimed or Skyped ...
(1) You were wise to test both OS X and Windows®! Strange behavior...
• Can you connect any change in internet service, system components, software, or other problems with the general timeframe of onset of camera trouble?
• Have you tested your camera with any apps that are NOT chat related (iMovie, QuickTimeX Player, Photo Booth, etc.?
iso250 wrote: ... I then found that opening and closing Facetime and Skype a number of times would sometimes "fix" the camera ...
(2) Does your cam have a "shutter" or privacy curtain that might not be opening completely?
Also, are you certain that you have ONLY one OS X app using the camera at a time?
• Be sure only one app is open. Restart Mac if necessary and launch only ONE.
• Check for camera POSSIBLY running in another user (switching) account.
• Check for login items or dashboard widgets that might be using your camera.
iso250 wrote:... Does anyone have any idea why this would be happening? I've looked for drivers for the webcam but have not been able to find any that rectify the issue....
(3) Perhaps some camera app or driver software you added is causing a conflict. If you added anything, follow the developer's instructions on how to uninstall it.
Do NOT install any software that may come with any Mac-compatible camera you intend to use with OS X. Every version of Mac OS X since 10.4.9 already includes all necessary software for every Mac-compatible camera.
This added software caution applies only to Mac OS X. For use with Windows® on your Mac Pro, feel free to install any compatible Windows® software your external cam may need.
iso250 wrote: ... Is there a setting of preference file that can be adjusted? ...
(4) Not likely. There is no system wide camera preference file in OS X. Because of the wide variety of possible camera functions, camera preferences are stored separately in each camera app's preference file.
You can check preferences and the other Apple Troubleshooting suggestions for your external (standalone) camera by using the tests suggested here: http://support.apple.com/kb/HT2090 .
Be sure to check more than one camera app in more than one user account.
Mac OSX 10.8.2 Mac Pro Quad Core (Early09) 2.93Ghz 24" LED Cinema Display External iSights
I tried resetting the PRAM. When I opened up facetime the picture was still black. I closed facetime and then opened up photobooth and the picture was perfect. I closed photobooth and then reopened facetimeand the picture was perfect. Looks like it was a PRAM issue although it was strange that I had to open a couple of pps before the picture worked correctly. That's very odd as part of my original fix when the issue started was opening those two apps one after the other.
I can't think of any change that occured around the time the issue started. I upgraded my graphics card about two months after the trouble started so that couldn't have been it. Fingers crossed if it happens again all I have to do is reset my PRAM again!!
Thank you all for your help. It's very appreciated and now I can skype with my Mum overseas gain.