audio not working after Mojave update on 2015 MB Air

I contacted Apple support on chat, and here is what worked for me.

go to this folder /Library/Preferences/Audio

and move these 2 files to trash

com.apple.audio.SystemSettings.plist

com.apple.audio.DeviceSettings.plist

then shut down and do a PRAM reset

Problem solved for the original issue that I reported above (under username OrionNebula) - it appears that there is apparently a design flaw (perhaps I should call it a 'feature') in the Mojave OS. If a window pops up and asks if you want to use the microphone, answering “no” (which of course is a natural thing to do for privacy reasons) will in fact disconnect >all< of your audio inputs, not just the computer’s internal microphone. Apparently, in this case, “microphone” apparently means 'all inputs' in Applespeak. Fortunately, you can switch them on again by going to System Preferences/Security and Privacy/Privacy/Microphone and checking the particular piece of software (Cubase in my case) to allow it to use all inputs - this will restore the ability to input audio into a program, from whatever source.

Also go to system information by holding down Option+clicking on Apple in menu bar, and selecting the first option.

Then click on audio and see if it matches what you see in this photo:

If you don't see this, boot into safe mode by rebooting and holding shift key until you get to the login screen. If you don't have any sound in this safe boot mode, then it is possible that there is a hardware problem and an Apple Store should have a look at your machine.

Try deleting the instant.on driver in /library/audio/Plugins/HAL and reboot

This worked out for me !!!

I had this issue as well, and while I did not mean for this to fix it...this is what worked after I spenttime looking for the stupid audio library files and couldn't get anything to work.

I was messing in System Pref...Sound, and I have an apple TV in my living room. I wondered if that would tell me if the audio would work on the Apple TV. I clicked AirPlay, the clicked back to Internal Speakers to check something else...and suddenly the iTunes music that was playing came blasting though the iMac speakers, and now it works.

Like I said, it's a stupid accidental solution, but in case it helps...

Thanks for this:

sudo killall coreaudiod

This worked. But I'm an IT guy, so running terminal commands and typing admin passwords to make audio work again isn't SUCH a big deal. But this bug IS annoying. Apple controls the whole stack. They can't really fall back on hardware incompatibility. What is happening here?

Try going to System Preferences > Security and Privacy. Click on “microphone” and see if your audio input software is listed. Ensure it is checked. This should fix mic and audio input issues.

It worked for me. After installing Mojave, myMac was showing that audio was indeed coming in through my capture device, but my software was not recording it. Fixing the privacy solved the problem.

I had the same issue. Try: MacOS Mojave- 

Go to System Preferences > Security & Privacy > Privacy and select “Microphone”. Any app that uses the microphone must have the checkbox selected. 

I guess the word “microphone” is this instance, is synonymous with “line in”.

Good luck.

This problem has been solved after removing RogueAmoeba InstantOn.driver plugin from /Library/Audio/Plug-Ins/HAL.

Tried everything you suggested here and none of them worked. The sound card worked ok when booted with windows. It is definitely a Mojave software issue. A very disappointing upgrade. Hopefully the fix will be out soon, or at least acknowledge this bug at first place then try to find a solution for Mac users. - Early 2015 MB Air

Please check that in System Preferences/Sound you see Internal Speakers activated like this under Output. Also the chime when booting up is different from the sound drivers working properly inside the booted OS.

I don't have the InstantOn.driver plugin. What else can I do?