silence when I reboot into High Sierra
Have the same problem on a 2010 white plastic macbook running high sierra.
Nothing I found on line worked. Then one day I booted it from a Linux Ubuntu install USB stick and the sound worked fine all the whie that OS was booted so mine is not a hardware problem.
It went back to silence when I rebooted into High Sierra. Does that tell anyone here what needs to be fixed on mine? thanks djc