Q: The volume on my mac doesn't work

Might be corrupted sound preferences ...

Open the Finder. From the Finder menu bar click Go > Go to Folder

Type or copy paste the following;

/Library/Preferences/Audio

Click Go the move both .plist files from the Audio folder to the Trash.

Restart your Mac. See if that made a difference ...

Hopefully one of these steps should solve the problem.

1. System Preference > Sound > Output > Internal Speakers

    Highlight  Internal Speakers / Headphones

    Make sure that Mute is not enabled.

2. Remove the headphone.

    If you see red light in the headphone port, plug the headphone

    in and out of the port 5 or 6 times to flip the microswitch inside.

    Sound output may be stuck in the digital mode.

3. Reset PRAM.  http://support.apple.com/kb/PH4405

4. Reset SMC.     http://support.apple.com/kb/HT3964

    Choose the method for:

    "Resetting SMC on portables with a battery you should not remove on your own".

5. Applications > Utilities > Audio MIDI Setup

    Audio Devices window

    Side Bar

    Click the Built-in Output.

    Under Mute any of the boxes checked? If so, uncheck it.

6. If none of these steps is helpful, plug in the headphone and reset SMC.

I had that same problem. What worked for me was to plug in the speakers and adjust the volume and unplug them again. Then you should be able to adjust the volume

Thanks worked for me

Thank you worked for me