Things I have tried:
- sudo killall VDCAssistant
- sudo killall AppleCameraAssistant (shows no matching processes found)
- Reset SMC
- Reset NVRAM
- Ran hardware test (shows no issues)
A few additional things to note: the camera´s green light stays on until I quite FaceTime or any other app that uses the camera (e.g. Photo Booth). Camera shows up fine under system report. The machine has never been opened.
Machine is a MacBook Air 2012 running High Sierra (latest version).
Finally, note that this may have started when I changed the system's language.