Following this advice, at one point I have used cmd lines to either disable or deleted the components...(such an idiot)
While sudo chmod a+r /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC still works, I get "No such file or directory" when I do next four commands to restore webcam.
1)sudo chmod a+r /System/Library/PrivateFrameworks/CoreMediaIOServicesPrivate.framework/Versions/A/Resources/AVC.plugin/Contents/MacOS/AVC
2) sudo chmod a+r /System/Library/QuickTime/QuickTimeUSBVDCDigitizer.component/Contents/MacOS/QuickTimeUSBVDCDigitizer
3)sudo chmod a+r /Library/CoreMediaIO/Plug-Ins/DAL/AppleCamera.plugin/Contents/MacOS/AppleCamera
4)sudo chmod a+r /Library/CoreMediaIO/Plug-Ins/FCP-DAL/AppleCamera.plugin/Contents/MacOS/AppleCamera
I don't know how to fix this issue. Can anyone enlighten how to tackle this issue. Thank you in advance.