MacBook Air external monitor goes off and on when using HDR setting

Question

MacBook Air external monitor goes off and on when using HDR setting

I have a 2020 MacBook Air M1 16GB running MacOS 13.2.1. I have it connected via HDMI to an external monitor, a 45" LG ULTRAGEAR+ running 3440 x 1440. The HDMI cable from the monitor plugs into a USB hub, which connects to the MacBook Air via one of the two USB-C ports. The monitor's single DisplayPort connection goes to a Windows PC.

When I select the HDR option under Displays in System Settings the external monitor repeatedly goes off and on, as if the signal to the monitor keeps getting broken. When HDR is turned off, everything seems to work fine. The physical HDMI connection is fine (nothing is loose, cable is not damaged, etc.). The two things I can think of are 1) the HDMI cable might not be "high quality" enough to maintain an HDR signal; it's under 5' long, which I've heard can be a problem with HDMI cables, or 2) the USB hub is somehow interfering with the HDR setting. I can't think of anything else that might be the issue. Does anyone else have this problem?

Thanks in advance for any guidance.

Posted on Apr 26, 2024 4:58 AM

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Answer 1

Apr 26, 2024 7:06 AM in response to Shannonballrun

I am using a M2 Mac Mini Pro with an 32-inch LG 4K display. When I enable HDR in the Displays panel, the screen blanks out for a couple seconds before resuming the HDR display. It does this again when I switch HDR off.

I am using a single Belkin HDMI 2.1 4K high-speed cable directly to the LG display.

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Answer 2

Apr 27, 2024 5:35 AM in response to VikingOSX

Thanks for the info, VikingOSX. This happens to me as well. Even before I had this problem. This sounds normal (a guess). Something new: this morning my monitor had the problem from my original post when NOT in HDR mode. So I switched to HDR mode and now no problem. Sounds like it could be the cable, or the lack of direct connection to the monitor. Or both. Not sure if there's a fix since my MacBook Air has only two USB-C ports and I need one for the power and the other for the USB hub, since I have several things hooked up. The downside to Apple's relentless hatred for ports rears it's ugly head again... On a side note, I wonder if a self-powered USB hub would make a difference?

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Answer 3

Apr 28, 2024 6:25 AM in response to Shannonballrun

Just to wrap this up and share with the community, I've solved the problem. I got an HDMI to USB-C cable and ran it from the monitor directly into one of the USB-C ports on the MacBook Air. To do this, I had to set up a bluetooth keyboard and mouse and dump the USB hub. Two ports still aren't enough -- I'll need to think of how to use my USB backup drive; I might have to get a wireless backup or something -- but for now it's working.

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MacBook Air external monitor goes off and on when using HDR setting

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