Why you can't change the volume of an HDMI monitor from your Mac

Why it happens

Over HDMI and DisplayPort your Mac sends sound as a digital signal at full level, and the monitor or TV sets how loud it plays. That's why the Mac's volume slider is greyed out and the volume keys don't change anything. Nothing is broken; the volume control simply lives on the screen.

How to fix it

1. Turn the volume up or down with the buttons on the monitor, or the TV's remote. On some monitors the volume is in the on-screen menu.

2. Want to use the Mac's volume keys instead? Open System Settings > Sound and, under Output, choose your Mac's speakers or your headphones.

   Sound›Output

3. Check the Output volume slider. With the Mac speakers or headphones picked, it's no longer greyed out and the volume keys work again.

Still not fixed?

1. No sound from the monitor at all? Pick the monitor or TV by name in the Output list, then turn up its own volume.

   Sound›Output

2. Headphones plugged into the monitor's headphone socket still follow the monitor's volume, not the Mac's. Plug them into the Mac to use the Mac's volume control.

3. If the monitor isn't listed under Output, unplug the cable at both ends and plug it back in, or try a different cable or port. Some adapters carry picture but no sound.

4. If the monitor's own volume buttons don't change the sound either, the problem is with the monitor or TV. Check its manual or contact its maker or a repair shop. If other screens behave fine but your Mac's sound settings misbehave, contact Apple Support.