Display keeps turning off after 30 seconds no matter what the settings say.

Sorry, the differences is that those screenshots are for a laptop and not a desktop Mac.

Try adjusting your "Turn display off when inactive" setting up to 20 or 30 minutes to see if that helps.

Also do your external displays have a standby sleep timers in their On Screen Menu settings?

If they do, then you may need to adjust those standby or sleep timers to never.

Hello, I have had a similar issue with my Mac Air with M2 chip when connecting to a Samsung external monitor. It turns out that it was the USB-C adapter that I was using. The adapter was an Apple branded device with a USB-C, HDMI and USB port.

I had tried everything in this thread, a different HDMI cable, a different monitor and finally I noticed the adapter was warm to the touch and purchased a different branded adapter and the problem was solved. I was also on the phone with apple support for an hour and one of the suggestions was doing a factory reset to the machine, which I did not want to do.

Have you tried resetting the SMC in Terminal?

"sudo pmset restoredefaults"

Without the quotes and key in the admin password which you won't see being typed.

Restore default power management settings - Apple Community

Or Desktop computer

If your Mac isn't a laptop computer, follow these steps:

1. Shut down your Mac, then unplug the power cord.
2. Wait 15 seconds, then plug the power cord back in.
3. Wait 5 seconds, then press the power button to turn on your Mac.

To find out if it's system wide or user specific, try this...

Open System Preferences>Users & Groups, unlock the lock, click on the little plus icon, make a new admin account, log out & into the new account.

Does it work in the new account?

Sounds like you have missed something in Lock Screen and/or Displays.

see > Set sleep and wake settings for your Mac - Apple Support

Jerry_D wrote:

Thanks again. I've tried many different settings in the Lock Screen menu, but the problem refuses to go away. And no, the external screens have no sleep timers of their own. I can't be 100% sure, but I do not remember this problem before upgrading to Sonoma. Will report it to Apple as a possible bug.

That is a good idea.

You can send Feedback directly to Apple,

by using > Feedback - macOS - Apple

and > Feedback - Mac mini - Apple

Or by contacting Apple Support,

at > Official Apple Support

Hi, I was having a similar issue but it would turn off after 9min, no matter what I did. I finally bought another non-apple adapter, which has worked flawlessly since then. That was the last thing left to try. Best of luck.

Post snapshots please of how it is now.

That’s not the setting on the link and your previous snapshot was truncated. Furthermore, the Energy Saver settings haven’t changed and are snapshotted here from Sonoma just to make the point absolutely clear:

Anyway, turn Wake off and freeze these settings permanently, irrespective of whether or not it fixes the problem. But it should. Do update.

I’m afraid based on how long it took me to get to this point, I can’t take your word on it. SO, please post a snapshot confirming the settings mirror what I’ve posted please and confirm they will stay that way irrespective of whether you think that’s relevant or not.

And then add some detail on the two monitors - make & model would be perfect.

I just found a temporary solution for my problem (apps shuffled after display off). Just set the screen saver to 1 minute; set "required password after screen saver starts" to immediately.

When I want to leave my desk, just don't touch the mouse or keyboard until the screen saver starts.

😅

Er, no. Don’t care about Lock Screen. Please post snapshots referring to the settings shown here Wake up a remote Mac mini - Apple Community.

Jerry_D wrote:

I have my Mac mini connected to two monitors via USB-C cables. Regardless of the settings under Lock Screen, after I lock the computer, 30 seconds later the displays turn off and (I guess) the Mac goes to sleep. Is this a bug or am I missing something?

No the Mac does not go to sleep it simply is killing the signal to the display to prevent burn in. This is likely by design and I have the same thing in my set up using lock screen. There is zero to worry about and is actually a good thing. Unless you like having pixels being burned into the screen and your monitor burning energy for an image which likely no one is going to sit and stare at for hours.

Use the settings shown here Wake up a remote Mac mini - Apple Community, might fix.