Fixing iSight camera not found or working under Mac OS X
From Wikistix
Searching around, there seem to have been many reports over the years with Apple iSight built-in cameras not working or not found. My parents regularly have this issue on a fully up-to-date, recent iMac running Mac OS X 10.14.4 as of May 2019.
In all cases so far, killing the VDCAssistant process has brought the camera back to life, without rebooting or restarting apps.
bash$ ps u -p $(pgrep VDC)
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
_cmiodalassistants 54904 0.0 0.2 4340228 14436 ?? Ss 5:05PM 0:34.10 /System/Library/Frameworks/CoreMediaIO.framework/Resources/VDC.plugin/Contents/Resources/VDCAssistant
bash$ sudo pkill VDCAssistant
