Q: MacBook Air no audio output device found ???????? *please help*

It didnt actually cost anything because of EU law. Ive had the macbook less than 2 years and theres no visiable faults/Scratches to the machine so they had to repair it for free.

After loosing sound again, I placed the audio cable back in the original "under-the-battery" position and I have reliably had sound for two weeks. This definitely seems to be more on the hardware side (at least in my case) but I so far have been able to repair it without replacing any parts or even spending a dime.

i also tried rebooting, plugging in and out, SMU reset, PRAM reset, repair permissions, deleting ~/Library/Preferences/com.apple.BezelServices.plist   ...no joy.

finally stumbled on this one:

Macintosh:~ user$ sudo kextunload /System/Library/Extensions/AppleHDA.kext

Password:

Macintosh:~ user$ sudo kextload /System/Library/Extensions/AppleHDA.kext

and voila!

Macintosh:~ user$ sudo kextunload /System/Library/Extensions/AppleHDA.kext

Password:

Macintosh:~ user$ sudo kextload /System/Library/Extensions/AppleHDA.kext

Worked for me! (At least so far). Thanks!

A few notes:

1. I had a headphone plugged in while trying this fix, but I'm not sure if the headphones had any effect on fixing.

2. sudo kextunload /System/Library/Extensions/AppleHDA.kext gave me an error that the file didn't exist. But I just continued with the second command anyway (sudo kextload /System/Library/Extensions/AppleHDA.kext), which worked fine. Then I input the first command again, then the second one. No errors this time.

3. I then rebooted and got the startup chime, and my audio is back.

This solved my problem. Was showing "no audio output device found" in system preferences<sound<output. Now it's back to normal! Thank you!!

Hi folks, maybe I have some things to add to this discussion, but no permanent fixes yet.

I've had similar problems getting sound from internal speakers on my MacBook Air, OS Mavericks.  Upon startup one day, I suddenly had no sound.  Here is a list of what happened.  It’s weird.  Sort of a hodgepodge of the symptoms and fixes I've read about so far.

1.  At first, the volume buttons on the keyboard would cause the transparent image with the white blocks and speaker emblem to appear, but this would lag horribly (sometimes up to 10 or 15 seconds after pressing the buttons), and they still weren't making the characteristic mac "pop" that you're used to when you turn the volume up and down.

2.  After checking System Preferences/ Sound and toggling the buttons a few more times, the volume icon at the top of the desktop went gray, the "internal speakers" option in the sound preferences pane disappeared and read "no output device found" or something like that, and of course I still had no sound.

3.  I tried rebooting, but this changed nothing.

4.  I tried plugging headphones in and out a few times, but this changed nothing.

5.  I tried repairing permissions in the disk utility, but this changed nothing.

6.  I tried playing sound a number of ways including through iTunes, youtube, and Reason, but this did nothing.  Interestingly, when I pressed space bar on some .wav files to “preview” them in finder, they would not play.  That is, not just no sound, they also did not play in the reel even though I pressed the “play” button.

7.  I tried deleting the file Library/Preferences/com.apple.BezelServices.plist, but this did nothing.

8.  I tried deleting the files Library/Preferences/Audio/com.apple.audio.DeviceSettings.plist and ./com.apple.audio.SystemSettings.plist, but this did nothing.

9.  I tried logging in as a different user, which took me back to the situation described in 1., but still no sound.

10.  I tried restarting in safe mode, which seemed to do nothing, but then when I restarted in normal mode everything was fixed!!!  I had sound, and “internal speakers” was selected in the Sound preference pane.  But this only worked for about 10 minutes, and everything went back to how I described it in 2.

11. I tried a bit of prodding in the headphone jack with a toothpick, but nothing.

12.  I tried deleting the file Library/Preferences/com.apple.audio.AudioMIDISetup.plist, and this brought the sound back!!!  But as soon as I tried “previewing” .wav files in finder as before, the situation described in 1 came back.  Now it’s laggy volume buttons and no sound.

13. Upon rebooting in safe mode and rebooting in normal mode, I’m in situation 2 with the grayed out volume control at the top of the desktop, the circle with the slash through it when the transparent sound thing pops up, “no output devices found” in the sound preference pane, and of course no sound.

14. Tried wiping the PRAM with control + option + p + r at startup, and this worked!!!  Sound is back!!!  Until… yeah, of course, I tried “previewing” some audio files with space bar in finder and I’m back to situation 1 with the laggy volume buttons and no sound output.  This time I tried previewing .m4a files in finder rather than the pesky .wav files I had tried before, just in case there was an issue with file type or the .wav’s were corrupted.

Anyway, I’m at a loss.  I think for round 15 I’ll try dancing, chanting, and burning incense, or maybe I'll just order a beer.  Unless someone has an idea, I’m headed to the genius bar when I get home.

The latest:

15. Turn off your laptop and leave it charging somewhere.  Order a beer, sit on the beach for a couple of hours, pet a cat, listen to In A Silent Way, schedule a Thai massage, and change 1000 THB for smaller bills so you can tip the masseuse later.  Then fire up your laptop, and the sound will work.  So far it isn't reverting back to no sound when I try playing audio files, either.  Crossing my fingers...

Just got the problem solved:) at least at the moment..I had the same problem with my mid-2011 MBA since few months ago after I update my OS to yosemite. Soon I had the issue, I read this post and I did all the Bezel preference file, smc...etc stuffs which was all fail (expect I didn't try reinstalling OS X). I left my MBA with no audio and use my bluetooth headphone as an alternate audio output. it is not that ideal but at least it works. I wished OS X EI Capitan could solve the problem but it couldn't. After several attempts of PRAM and SMC reset on the updated OS X, I guess I had accumulated just enough frustration to screw open the case. I surely am inspired by the audio cable method you guys mentioned. I opened the case of my MBA, unplug the speakers from both side and reconnect them again and this god THE SOUND COME BACK! Hope it will last.

I'll admit I don't know anything about anything technological, but it seems to me that this is an energy saving issue:  when the computer sleeps, the speaker shuts down.  I had the problem for weeks and tried many of the solutions on here, but to no avail.  So I went to System Preferences and then to Energy Saver.  Under the Power Adapter tab, I changed my settings to turn display off NEVER.  But now my speakers never shut off, and when I close the computer, the display does turn off then, but the speakers do not.  The battery may not last as long, but it has worked for me.