Mac Volume Not Working? Why the Keys Do Nothing and How to Fix It

You press the volume keys and nothing happens. Or the on-screen indicator appears with a line through it, the slider in the menu bar is greyed out, and the Mac’s volume is not working at all.

This is almost never a broken keyboard. In most cases macOS is telling you, without explaining it, that the device playing your sound is in charge of its own volume.

Why macOS Sometimes Cannot Change the Volume

For built-in speakers and most headphones, macOS sets the volume itself. For some outputs it hands the sound over untouched and leaves the volume to the device.

That is typical of monitors and TVs connected over HDMI, DisplayPort, or USB-C, and of many USB audio interfaces and DACs. With one of those selected as the output, the volume keys do nothing, the slider in System Settings > Sound is greyed out, and the on-screen indicator shows that volume is unavailable.

Nothing is broken. The Mac is waiting for you to use the device’s own controls.

Fix 1: Check Which Output Is Selected

Open System Settings > Sound and click Output. Look at the selected device.

If it is a display, TV, dock, or audio interface, that explains the dead keys. You have two choices:

Keep that output and change the volume on the device: the buttons or on-screen menu on a monitor, the remote for a TV, or the knob on an interface.
Switch the output to your Mac’s speakers or your headphones. The volume keys start working again immediately.

Fix 2: Make the Mac’s Keys Control a Monitor

If you want to keep using a monitor’s speakers and control them from the keyboard, you need an app that talks to the monitor.

MonitorControl is free and open source. It sends volume and brightness commands to many external displays over the display cable, so the Mac’s volume keys can control them. It does not work with most TVs, DisplayLink docks, or the built-in HDMI port on some Macs.

Paid apps such as SoundSource take a different approach and adjust the sound in software before it reaches the display. Either way, this is something macOS does not do by itself.

Fix 3: Check the Function Key Setting

If the volume keys do nothing on any output, including the built-in speakers, check how the top row is set up.

Go to System Settings > Keyboard > Keyboard Shortcuts > Function Keys. If Use F1, F2, etc. keys as standard function keys is turned on, the top row sends F10, F11, and F12 instead of mute and volume. Hold Fn (or the Globe key) while pressing them, or turn the setting off.

With an external keyboard that is not made by Apple, the volume keys may need the keyboard’s own function lock or a different key combination.

Fix 4: Restart the Sound Service

Sometimes the slider moves, the indicator changes, and the actual loudness stays the same. If the app’s own volume and the device’s own volume are both up, the Mac’s sound service may be stuck.

Restart it from Terminal:

sudo killall coreaudiod

Enter your Mac password. Sound cuts out briefly and comes back. This will not help if the output controls its own volume. Avoid doing this during a call or a recording. Our guide to sudo killall coreaudiod explains what the command does.

Fix 5: Check Mute and Balance

If the volume changes but you hear little or nothing, the problem may not be the volume at all.

In System Settings > Sound, make sure Mute is not ticked. Then check the Balance slider under Output. If it has been dragged all the way to one side, one speaker or one ear goes silent, which can sound like very low volume. Drag it back to the middle.

If there is no sound at all, work through our guide to Mac sound not working.

Let an App Tell You Which One It Is

Soundshine Doctor is a free Mac app that looks at the current output and tells you what it found. In each device’s details it tells you when the volume is managed by the device itself, so you know the keys are not supposed to work.

It also shows mute and the left and right balance, and its Quick Fix button can restart the sound service for you without Terminal. It will not do that while an app is using a microphone, so it does not cut off a call, and it asks for your Mac password because macOS requires it.

Doctor cannot add a volume control to a display that does not offer one. For that you need the monitor’s own controls or an app like MonitorControl. It needs macOS 15 or later.

Download Soundshine Doctor free. No account, and Doctor never records audio.

Frequently Asked Questions

Why are the volume keys not working on my Mac?

The most common reason is that sound is going to a device that controls its own volume, such as a monitor connected over HDMI, DisplayPort, or USB-C, or a USB audio interface. macOS often cannot change the volume of those outputs, and when it cannot, the keys do nothing and the volume slider is greyed out.

How do I change the volume on an external monitor from my Mac?

Use the buttons or on-screen menu on the monitor itself. If you want the Mac's volume keys to work, the free open-source app MonitorControl can control many monitors directly, or you can switch the output back to your Mac's speakers or headphones.

Why is my Mac volume stuck or greyed out?

A greyed-out slider means the selected output does not let macOS set its volume. A slider that moves while the sound level does not change can mean the sound service is stuck, and restarting it often helps.

Can an app fix volume keys that do nothing?

It depends on the cause. Soundshine Doctor, a free app, tells you when your output controls its own volume and can restart a stuck sound service. It cannot add a volume control to a display that does not have one.