My audio only works from the headphone jack and for a long time I thought it was a hardware issue. When I unplug from the headphone jack, I see the loudspeaker icon with the error-icon on the bottom.
But recently I discovered it’s most probably faulty OS audio-drivers because everything worked fine when booting my MacBook Pro from a friend’s hard drive.
So can I specifically reinstall just the audio-drivers. I couldn't find any info online so I’m afraid I would need to do a complete reinstall.