No Sound on MacBook Air

Hello, I have recently got an issue with my Macbook Air that is its sound stopped working. Till now I used to restart it and the sound starts to work but from two days back even after restarting the sound has stopped and wont work after restarting as well. Now I can only see the image of the speaker to be grayed out and there is no output device listed under sounds. I have also tried to update Mac software but still am not sure that it can be repaired. So therefore I come here seeking for a solution for this. Thank you

I've been having this problem too! And the following got my sound back!

Delete the following file:

~Library/Preferences/com.apple.BezelServices.plist

Restart your computer.

This worked for me. Download tool call ONYX. Use it to repair disk Permission. (dont know if this is necessary but good practice anyway) There is a cleaning menu. Clean out the audio cache. (among other things (I didnt touch the kernel !) it will prompt you for a restart and you should hear the chime.

There are several cases where MacBook Air loses sound capabilities. Several users have reported an issue in which the MacBook Air suddenly becomes unable to output sound. When this issue manifests, the sound icon in the menubar may disappear, and no output devices may be listed in the Sound pane of System Preferences.

This issue can only be resolved via authorized Apple repair. Contact Apple support or bring your MacBook Air to a local Apple retail store for assistance.