no audio after installing High Sierra

User posted this solution:

Issue Solved!

I have uninstalled Airfoil and Airfoil Satellite and removed audio plug-in "instantOn.driver" that was causing the issue!

Removed it from:

/Library/Audio/Plug-Ins/HAL/

InstantOn.driver

and

/Library/LaunchDaemons/

com.rogueamoeba.instanton-agent.plist

Detailed solution is on this link:

High Sierra 10.13 no sound slow browsing | Apple Developer Forums

Re: macOS High Sierra no audioRe: macOS High Sierra no audioRe: macOS High Sierra no audio

Get help if the internal speakers on your Mac don't make sound - Apple Support

Reset your NVRAM:

Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, and recent kernel panic information.

https://support.apple.com/en-us/HT204063How to reset NVRAM on your Mac - Apple Support

Poheto wrote:

Possible decision is to delete /Library/Audio/Plug-Ins/HAL/InstantOn.driver/Contents/MacOS/InstantOn if it exists.

FWIW, there is no "/Library/Audio/Plug-Ins/HAL/InstantOn.driver" in my installs.

For those that shows Internal Speakers under Audio Output, I many have a solution for you. In my case, the mute button was permanently grayed out in System Preferences. No audio would come out of my speakers or headphones.

NVRAM and SMC resets did nothing. Reinstalling Mac OS through Recovery Mode or the App Store did not fix the issue either. Interestingly, if I double clicked on the system sound effects found under Sound in System Preferences, they would play through both the speakers and headphones.

My solution was to go to Midi Audio Setup, select "Built In Output" from the sidebar. Then click on the gear icon towards the bottom of the window and select "Use this device for Sound Output." It should then work!

I had the same issue as you MarkFly. My audio stopped working, and I didn't have the InstantOn driver.

The solution that worked for me was to reset the PRAM. Shut down your computer. Turn it on, and immediately press and hold down Option+Command+R+P. Wait until you see a grey/lit up black screen, and then release. Solved all audio issues!

Thanks so much for this solution! Even though "use this device for sound output" was greyed out on my settings "gear" menu, I toggled the "mute" boxes to the right of the "Master" stream setting on and off and then adjusted the volume in the task bar. Works perfectly now. It even fixed a "buzzing" speaker problem I had! Awesome!

This finally worked on mine.! Thank you. I had not wanted to update, but the computer somehow did it automatically and of course the internal speaker went away. I tried all of the other items, but they did not work and restarted many times. Finally I did the steps on this link and shut down and then restarted. A smile came on me when the chime of the restart was heard!

Hello my friend.

It's unbelievable... This happened also to me, but, with my external sound card. (M-Audio, Fast Track pro.)

It's supposed to improve compatibility with some external USB sound devices...

I'm looking forward to downgrade to 10.13.1...

Good luck...

I'm using a 2017 13" MacBookPro with touchbar, running the latest HighSierra. I can't get any internet video to play in Safari--FB, Messenger, YouTube, whatever. iTunes Library plays just fine. Looked for every possible setting I can find--the proper output device is selected (tried speakers & headphones), volume all the way up, nothing "muted," the Sounds "Enabled" checkbox in FB and FB Messenger is checked. Toggled Bluetooth on & off. Please don't give me some command-line gibberish to type--I don't have any of the programs that the other questioners seem to have, so no extensions or plug-ins to enable or disable. If I wanted to play with command lines I'd still be running MS-DOS on a PC.

Going to try Firefox but not hopeful. I'm never installing OS updates again until they're bug-free.

After upgrading to High Sierra on my Mac Pro Sound defaults to Digital Out and will not stay on Line out. Apple tech support tried restarting computer with numerous holding down keys to no avail. I was referred to a retail tech support shop who suggested I unplug anything attached to the computer not related to the key board and monitor as a process of elimination. I tried this and this did not solve the problem. I even tried spraying compressed air into the optical output port as I read dust could be causing the problem. That did not work. HELP!!!!!!!!!!!

It could be the system is set to Mute.

Go to System Preferences > Sound

Is the slider set to mute? I suggest checking show volume in the Menu bar. Easy to reset. For me personally, almost every time I restart, it's set to mute.

See this post it might help you with the issue:

Coreaudio issues High Sierra | Apple Developer Forums

I have the exact same issue! Worst update ever! By this moment no one could help.

Possible decision is to delete /Library/Audio/Plug-Ins/HAL/InstantOn.driver/Contents/MacOS/InstantOn if it exists.