Update to MacOS 27.0 breaks Streaming / BBC iPlayer / YouTube playback.

Try this

If your M1 Mac Mini is connected to an external display via HDMI or DisplayPort, macOS 27 has a specific bug that breaks video playback when audio is routed to certain primary monitors.

• Open System Settings and go to Sound.
• Under the Output tab, temporarily switch your sound output away from your main monitor (e.g., switch to Mac Mini Speakers, a secondary monitor, or a pair of headphones).
• Test a YouTube or BBC iPlayer video to see if playback immediately resumes. 

For me, on another Mac type, video playback is working just fine

M2 studio, fighting this for a while, midi adj MIDI Audio configuration and change audio frequency format to whatever is not 48 kHz. Pick 44, 88 or 96. And it works(from Reddit), also turn monitor off and on works, I had tried a reinstall of 27 not fixed, await patch

I found the fix for this in my case with LG monitors. AI (ChatGPT) told me Apple's documentation on macOS 27 (maybe updated docs) says:

1. Open the Audio MIDI Setup app.
2. Select the sound output you're having a problem with.
3. Check the format and change it if it's set wrong. The setting there can be corrupted during upgrade.

In my case, it was set to what I've seen other Mac users' settings were set to, "2 ch 24-bit Integer 48.0 kHz". I changed it to "2 ch 16-bit Integer" and the sound output started working again. I changed it back to what it was set to originally, and it still worked. So, I don't know why, but I assumed something got corrupted and that just overwrote the corrupted setting to fix it.

BUT, today it stopped working again, two days after I fixed it this way. I went and did the same things, it looked the same way, and it was fixed exactly the same as before. So, I assume there will be many, many updates coming for macOS 27 to fix bugs like this.

Another update as someone in here mention about "Audio MIDI Setup". Actually it works. You can follow these steps.

Steps to Force Audio Output to not be 24-Bit

1. Open Spotlight Search by pressing Command + Space (or go to Finder > Applications > Utilities).
2. Type Audio MIDI Setup and press Enter.
3. In the left sidebar of the Audio Devices window, click on your target output device that you want to use. In this case, it will be our monitor.
4. Look at the Format dropdown menu under the Output tab.
5. Select a 20-bit option paired with your desired sample rate (e.g., 20-bit Integer at 48.0 kHz). If it doesn't work then lower to 16-bit.

It works on my LG monitor.

Had the same issue, Streaming don't play, locally stored QT videos don't play, switching to the Mac mini (M1) speakers worked for me, videos play.

However why this would happen at all is pretty bad, I just updated to 27.0.1, did not help.

I hope Apple can fix this soon, don't want to listen through the small tinny speaker.

• I'm using a secondary display through the HDMI port

Wow, it took me a while thinking it was the streaming service, then I saw it happened with all services, and not on other devices. So a quick search took me here.

I have multiple computers that I connect to my monitor, so by using the monitor audio output to go to my speakers, allows which ever computer video input I have selected will get the audio as well.

This is a very silly bug and I hope it is fixed in the next update.

Update,

I reinstalled Goden Gate

• did not change

My mac did a couple of "strange" reboots before I could log in

• Still videos would not play

Several hours later I shut down my Mac mini, after I started it again, videos play and everything is as it was before.

I don't know what fixed it

Further to the os27 2 external monitors fault/problem

Sound alert stops working if you move from internal Mac speaker and will not work until restart the coloured spinning wheel appears when fault occurs 

Further to the os27, 2 external monitors fault/problem

Sound alert stops working if you move from internal Mac speaker and will not work until restart, the coloured spinning wheel appears when fault occurs 

Further to the os27 2 external monitors fault/problem, may or may not be related, when leave my m2 Mac Studio in standby the main monitor (usb 3 to Dp connection) occasionally turns backlight on and after a short time turns backlight off,the no signal standby light on monitor stays on the whole time, when monitor reset fault goes away for a while but returns, this is a new behaviour since os27 update

I happened to have my sound set to internal speaker today when it stopped working again, the same as you describe, it hangs anything trying to play sound, including Youtube videos.

I fixed it again by opening the Audio MIDI Setup app and changing the setting on the affected monitor to a different setting.

Just for testing, I'm going to leave it on the setting that fixes the sound bug and leave it on that setting to see if it happens again in 3 days. Maybe it's the setting itself. I don't really care with a simple, loud sound feedback that I use the monitor sound for, I just need it to work because the internal speaker is impossible to hear in a non-silent room.

This also confirms that the bug is recurring about every 3 days and this fix is only a band-aid.

With all the people who buy LG monitors, it seems very strange that macOS 27 ever got out of beta testing with this bug. It almost makes me want to turn on beta updates, because it's obvious I'm already running beta software.

This happen same to me too after I upgrade OS. I use M1 Pro on Macbook Pro.

At first I thought networks issue due this happen even I use Youtube on Google Chrome. Changing Browser won't help at all.

Only solution for now is change sound output to use internal speaker, headphone or audio device from USB. For speaker via HDMI, now it's useless.

I have the same issue on my 2024 M4 Mac Mini (32 GB RAM, 2 Tb SSD). I did a clean install of MacOS 27.0.1 without restoring, so there should be no conflicts with older software and startup items. I'm still having the same issue with video playback and Dock malfunctions. Internal or external speakers make on difference. This OS feels like an early beta release. Time to restore my 26.7.1 backup.

still no fix ? macOS 27.2 Golden Gate RC Release Notes

Display Settings

Known Issues

When an external display is connected, display settings might not be restored correctly, and the display arrangement might change. (188643179)

Same issue on my MacBook Pro. Specific to running HDMI out to a second external monitor. But that's how my home is set up, and it worked before OS 27; 27.0.1 did not fix it. We should not have to dig into workaround settings with a new OS release!