No Audio Output

If your Macbook appears to have no audio output, use either of the methods described here to open up your Sound settings. You may see that none of the available output devices are selected; in this case, select one, probably Macbook Air Speakers. Additionally, make sure that the volume level is neither set to 0 nor muted. If Macbook Air Speakers is not available at all, try restarting your computer and repeating these steps to check for its presence.