HDMI audio

Hello Mac-Tommy,

The key to finding a solution to an issue like this is to isolate exactly what is causing the problem.

First, restart the Mac. Power cycle the Mac using these instructions: Shut down or restart your Mac - Apple Support While simple, this can refresh the macOS, apps and connections.

If the issue remains, replace the hdmi with another cable and see if that helps.

If possible, use the cable with another device, on both ends, and see if it works as expected.

If you are able to determine that he HDMI cable is good, and the device it is connected to works as expected, then we would turn our attention to the Mac itself.

We would suggest starting up the system in what is called safe mode. Safe mode only loads what is needed to run the computer. This can help isolate what is causing issues.

To start in safe mode, follow these steps:

1. Shut down your Mac.

2. Turn on your Mac and continue to press and hold the power button until you see the startup options window.

3. Select your startup disk, then press and hold the Shift key while clicking “Continue in Safe Mode.”

4. Log in to your Mac. You might be asked to log in again.

More information is available here: How to use safe mode on your Mac - Apple Support

The computer will take longer to start in safe mode, and the screen may have some distorted video as it starts up. This is normal. Once you are logged in, use the system and test to see if the issue continues.

If everything seems to work as expected, go ahead and restart the computer normally and test again. There are steps outlined on what to do if the issue does or does not continue in safe mode.

Starting in safe mode also forces the computer to run some disk checks similar to First Aid. This can actually resolve some issues.

Have a good day.

Thank you for the reply Mac-Tommy!

Rebooting the computer was a great step to take. Were you able to test to see if this occurs in safe mode? As mentioned previously, safe mode only loads what is needed to run the computer. This can help isolate what is causing issues. Let us know if this occurs in safe mode.

Also, please let us know what your exact set up is. You have your HDMI cable plugged into your Mac, but what is it connected to on the other end? When you tested your son's computer with the same HDMI cable, was it connected to the same device on the other end? This can help us further isolate the issue.

Keep us posted.

I have this problem too and the only way to fix it is to reboot the Mac when plugging it in to the external monitor. This is happening with both my personal M1 MBP 13" (with USB-C adaptor) and work M1 MBP 16" (via built-in HDMI). This means these laptops aren't very portable :/

If anyone has a way of restarting audio via the Terminal that might be a easier fix than a full reboot, that would be great.

Hey there Mac-Tommy, 

What exactly are you connecting the HDMI cable to? A monitor or something else? Are you using any sort of adapter or hub along with the cable? Both of these details will be helpful to getting you pointed in the right direction.

Have a good one!

Mac-Tommy wrote:

I am using an LG 27" 4K monitor with built in audio. My son is connecting his M1 MacBook Pro to a 32' tv. And both no audio with HDMI.

Are you getting the screen display? If not, maybe you have not selected the correct HDMI port on the Monitor/TV settings.

What are you connecting to with HDMI?

OK, on the Mac mini, are you using the HDMI out? On the MacBook Pro, there must be an adaptor to go from USB C to HDMI?