LG Ultrafine 'black screen' after Mac Mini M2 (2023) goes sleep mode with YouTube playback

After doing some internal investigating, I think I narrowed down the issue to browser playback of YouTube videos after locking the device and letting it sleep after 5 minutes. The following are steps I've taken with the OEM (monitor) and also the OS.


This "issue" didn't start occurring until I upgraded to Sequoia.


OS version - 15.2 (24C101)


Browser - Firefox latest updates.


Device - Mac Mini M2 (2023) 8 GB of memory


External monitor connection

From the HDMI port on the M2 to the back of the monitor.


OS - Energy settings (enabled)

Prevents...display is off

Startup...power failure


OS - Lock Screen settings (updated)

Start Screen Saver ... Never

Turn display off when ... For 5 Minutes

Required password... Immediately


OS - Display settings (enabled)

High Dynamic Range

Refresh Rate - 60 Hertz

Color Profile - LG Ultrafine


External monitor General settings (enabled)

Deep Sleep Mode

Power LED


Repro Steps

  1. Using a third-party browser, navigate to YouTube and play a video that is greater than the timeout of 5 minutes.
  2. Lock the device and allow input devices to be idle (e.g. don't touch the keyboard and mouse or engage screen share from another device) for over 6 minutes.
  3. Return to the desktop after 6 or more minutes and review the blank screen of the external monitor.

Actual Result

The screen appears to be broadcasting the color black, which, when viewed from an angle, clearly looks like the monitor is still on.

Expected Result

The external monitor screen should be black and from an angle does not appear to be on.


Thoughts.

This is probably not the only example, and it might not be exclusive to YouTube videos. But I found this to be the most consistent.

Also, before someone asks, I will also try this with Safar and see if the issue occurs and update my analysis.


Thoughts?


[Re-Titled by Moderator]

Mac mini (M2, 2023)

Posted on Dec 28, 2024 10:37 AM

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Question marked as Top-ranking reply

Posted on Dec 29, 2024 11:10 AM

Most users now do not recommend using sleep. Only causes all kinds of issues. Just have the display turn off as needed as you have discovered.

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LG Ultrafine 'black screen' after Mac Mini M2 (2023) goes sleep mode with YouTube playback

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