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Since the camera is working in other applications the problem is with David. Probably a driver/direct show issue IMO. DID you try uninstalling and re installing David? when you uninstall make sure it is completely uninstalled. Then when reinstalling make sure all components are installed. You can also try getting the redistributables directly from Microsoft. I cant remember whether it's the .net or some other redistributable but one of them has given me a problem in the past (though not with David IIRC).