Hello,
I've upgrade to high sierra from El Capitan and have since lost audio. It worked correctly prior to this and since having upgraded I've struggled to get it back. I appreciate that the OS x is new but would like some guidance or reassurance on what to do. I also struggled to get my head around the original post as it appears somewhat out of date with the issues I've been currently having.
As a result of this, I therefore don't know what screenshots need attaching and thought it was best to explain what I could gather from the issue and then going from there. Since having upgraded I've not had any audio, no output or input devices found in 'System Preferences' 'Sound'.
I did find a post that Toleda had made outlining how to get ALC**** to enable audio on High Sierra but despite this installing correctly (i think), there's still no sound.