Mac Mini M4 - Random HDMI Blackouts

[ChpTrk]

I, along with a surprisingly large number of other M4 users, are tracking an issue in the Apple Community with seemingly random 2-4 second blackouts on monitors connected via HDMI to the Mac Mini M4. I wanted to see if anyone in the MacRumors community was experiencing the same and if they've found any potential causes or solutions. Any tips?

 

[PaulD-UK]

Static electricity?

 

[MacCheetah3]

https://forums.macrumors.com/threads/weirdness-with-4k-monitor-and-m4-pro-mac-mini.2446231/

 

[haralds]

After testing three high-quality 4K cables on my m4 mini Pro, I purchased an Anker 8K HDMI cable. It solved the issue with my Dell U3818DW. I prefer to use the Thunderbolt USB-C port for other things.

 

[MacCheetah3]

After testing three high-quality 4K cables on my m4 mini Pro, I purchased an Anker 8K HDMI cable. It solved the issue with my Dell U3818W. I prefer to use the Thunderbolt USB-C port for other things.

Indeed, at least some of us have resolved the problem with a high(er) quality/capability cable.

 

[Jeeve Stubbs]

Same problem here for the last 3 years or so with my Dell PC, Nvidia card, and Asus monitor from 2020, linked via Display Port cable. Never had this issue before. The three are good midrange devices from reliable brands, so I guess they're not the issue. Maybe the cable? I don't remember whether it came with the PC or was purchased online, but I suspect the latter. I've often read it's useless to splurge on a "high-end" cable (Monster, etc.), so I probably bought a cheap one and that's what I get.
That said, if you have an issue with an Apple cable, which I consider high-end, then it's either not a cable issue or Apple has had production defects.

 

[Che Castro]

Been using hdmi with a tv and don’t have these problems , using 2.1 hdmi monoprice slim cable

 

[Bazza1]

Issue with my M2 (and reports of earlier) as well. initially resolved by using USB-C out to monitor (Acer here), but eventually found a HDMI cable that worked. Seems very hit-and-miss, which suggests to me that Apple hasn't really got a grasp on HDMI output on their computers.

 

[Yvan256]

I, along with a surprisingly large number of other M4 users, are tracking an issue in the Apple Community with seemingly random 2-4 second blackouts on monitors connected via HDMI to the Mac Mini M4. I wanted to see if anyone in the MacRumors community was experiencing the same and if they've found any potential causes or solutions. Any tips?

I've experienced that problem, but it's when I'm using my Windows 10 gaming PC with an LG HDR WFHD (ultra-wide) display connected via HDMI.

I'm assuming these blackout problems are related to HDMI's HDCP (High-bandwidth Digital Content Protection) because this is exactly what's supposed to happen when the HDCP handshake is invalid (block the video signal to prevent piracy, which leads to a black screen).

This is why you should always connect your displays via anything but HDMI if you have the ability to do so.

 

[Jeeve Stubbs]

I've experienced that problem, but it's when I'm using my Windows 10 gaming PC with an LG HDR WFHD (ultra-wide) display connected via HDMI.

I'm assuming these blackout problems are related to HDMI's HDCP (High-bandwidth Digital Content Protection) because this is exactly what's supposed to happen when the HDCP handshake is invalid (block the video signal to prevent piracy, which leads to a black screen).

This is why you should always connect your displays via anything but HDMI if you have the ability to do so.

I'm using Display Port and have the same problem.

 

[LionTeeth]

Minis have always, always had display issues.

My 2018 i5 had to be sent in and motherboard replaced, which pretty much fixed it. One of the reasons I am so hesitant to replace it with anything.

Literally every modern mini iteration has had people report display blackouts. Crazy.

 

[Jeeve Stubbs]

Minis have always, always had display issues.

My 2018 i5 had to be sent in and motherboard replaced, which pretty much fixed it. One of the reasons I am so hesitant to replace it with anything.

Literally every modern mini iteration has had people report display blackouts. Crazy.

Were you using an Apple monitor?

 

[LionTeeth]

Were you using an Apple monitor?

No always hdmi to a tv

Actually at the start when I got it I was going thunderbolt to a Dell monitor or something. I forgot about that. That stopped working completely. Like just blank screen no matter what I did. Upgraded my space to using a 4k tv and it was always turning off.

I've been hdmi to a 4k tv since apple worked on it and it's been pretty rocksteady.

 

[Jeeve Stubbs]

No always hdmi to a tv

Actually at the start when I got it I was going thunderbolt to a Dell monitor or something. I forgot about that. That stopped working completely. Like just blank screen no matter what I did. Upgraded my space to using a 4k tv and it was always turning off.

I've been hdmi to a 4k tv since apple worked on it and it's been pretty rocksteady.

I see. I can already imagine Apple telling you "Macs are guaranteed to display properly on Apple monitors - we can't guarantee results with other brands".
Anyway, glad you've solved the problem. The alternative, I guess, would have been to switch to iMac or Studio Display.

 

[LionTeeth]

I see. I can already imagine Apple telling you "Macs are guaranteed to display properly on Apple monitors - we can't guarantee results with other brands".
Anyway, glad you've solved the problem. The alternative, I guess, would have been to switch to iMac or Studio Display.

Haha I can't remember if they said that or not. He did test it right there in the Apple Store. Absolute blank screen. Undeniable issue. So off it went for service. That was pretty satisfying to see.

 

[bapegg]

The problem is not just with the Mac mini or Apple computers in general. I have the same thing with my Dell Optiplex 7010 Micro.

The Mac mini has had issues with HDMI since the 2018 model if not longer. I never could get my monitors to work correctly with the 2018 mini when using HDMI to HDMI cables. The fix was using HDMI to USB-C cables.

I currently have 3 monitors connected to my M4 mini. Two are with the same HDMI to USB-C cables from my 2018 mini. The third uses HDMI to HDMI. And the third monitor will occasionally black out.

I am also running three monitors with my Dell 7010. All three are connected with HDMI to DisplayPort cables. And they will blackout every now and then too.

And I am using good cables with both computers.

 

[Bazza1]

Haha I can't remember if they said that or not. He did test it right there in the Apple Store. Absolute blank screen. Undeniable issue. So off it went for service. That was pretty satisfying to see.

When I bought my M2, I actually made a point of doing the initial boot / OS update at the Apple Store. Folks at Genius tables pulled out an Acer (not Apple) monitor and used the USB-C port from the Mini to the monitor to do it. Kinda made me smile. Little did I know it was a hint...

 

[Jeeve Stubbs]

Haha I can't remember if they said that or not. He did test it right there in the Apple Store. Absolute blank screen. Undeniable issue. So off it went for service. That was pretty satisfying to see.

Imagine this happening during a live Tim presentation, lol.

 

[Snow4maen]

I have also had momentary monitor blackout. It's only maybe two or three seconds at a time. Seems to happen if I slightly move the HDMI cable. I'm on a basic 1080 display not 4k, and I have a good HDMI cable. For me all my thunderbolt/USB - C ports are used up with dongles and external SSD/HDD. So it would be a real pain to use a USB C to HDMI adapter, and I feel I shouldn't have to. My main concern is if this get's worse. I should say most of the time it is fine. But I am worried that one day, I will get a black screen and it may need repair.

 

[Bazza1]

Imagine this happening during a live Tim presentation, lol.

There's a reason they no longer do their annual love-in live. Even events that Jobs hosted had their bugs. And Tim isn't the showman Jobs was to cover it.

 

[ChpTrk]

After testing three high-quality 4K cables on my m4 mini Pro, I purchased an Anker 8K HDMI cable. It solved the issue with my Dell U3818DW. I prefer to use the Thunderbolt USB-C port for other things.

After about 2 weeks, I have to agree that this may be the solution. Haven't had this issue since using this cable. I saw this posted here and in the Apple forum. Thanks for the tip.

 

[bapegg]

I've been using HDMI to USB C cables since buying my 2018 mini years ago. I had issues with HDMI to HDMI with the 2018 mini. I have 3 monitors hooked up to my M4 mini. one of them is connected with a HDMI to HDMI cable and it occasionally blacks out while the tow using HDMI to USB C cables do not.

It's definitely something with HDMI since I have the same issues with my Dell Optiplex 7010 Micro using HDMI to Display Port cables. I did add a USB C port to it and need to test one of the monitors with a HDMI to USB C cable to see if it blacks out. None of my monitors have a Display Port.

 

[Che Castro]

Same problem on 2018 Mac mini

 

[trytime]

I’m running a basic Mac mini M4 with a three-monitor 4K setup — all three LG monitors are identical. For consistency (and due to some external limitations), I have all monitors set to HDMI source 1 when connected to the Mac mini.

• 2 monitors connected via USB-C → HDMI cables
  (Highwings USB-C to HDMI, 3m, 4K@60Hz, gold-plated, Thunderbolt 3 compatible)
• 1 monitor connected via a direct HDMI → HDMI cable

The two USB-C connected monitors run flawlessly. However, the direct HDMI monitor has recently started randomly cutting out — the screen goes blank for 2–3 seconds, then comes back. This issue only affects the HDMI connection.

What I’ve already checked

• All cables are securely seated.
• No visible damage to the HDMI cable or port.
• Displays are correctly configured in macOS Sequoia.
• The issue only started after a recent 2025 macOS update.

Has anyone with a similar 3-monitor setup seen this happen only on the HDMI output?

 

[bapegg]

I’m running a basic Mac mini M4 with a three-monitor 4K setup — all three LG monitors are identical. For consistency (and due to some external limitations), I have all monitors set to HDMI source 1 when connected to the Mac mini.

• 2 monitors connected via USB-C → HDMI cables
  (Highwings USB-C to HDMI, 3m, 4K@60Hz, gold-plated, Thunderbolt 3 compatible)
• 1 monitor connected via a direct HDMI → HDMI cable

The two USB-C connected monitors run flawlessly. However, the direct HDMI monitor has recently started randomly cutting out — the screen goes blank for 2–3 seconds, then comes back. This issue only affects the HDMI connection.

What I’ve already checked

• All cables are securely seated.
• No visible damage to the HDMI cable or port.
• Displays are correctly configured in macOS Sequoia.
• The issue only started after a recent 2025 macOS update.

Has anyone with a similar 3-monitor setup seen this happen only on the HDMI output?

Yes that has been happening for me ever since the 2018 Mac mini and still happens with my M4 mini. The two monitors connected HDMI-USB C are fine but the one connected HDMI-HDMI will occasionally black out for a few seconds.

The HDMI port issue has been known since the release of the 2018 mini.