Mac mini M4 Pro sporadically loses connection with external monitor

I have the same issue, with monitor not coming back on, ever after reboot. I thought it was my monitor, a KTC 32 Inch 4K Mini LED Monitor, Fast IPS, HDR1000 144Hz 1ms MPRT Gaming Monitor

https://www.amazon.com/dp/B0DDNVG1MK?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1. Luckily, but sadly, I'm using an older, smaller monitor until I can figure out what to do. the new monitor passed it's return date on Amazon, so wrote the company, but haven't heard back. I really liked the monitor otherwise.

I redid my settings. I'll try hooking the new monitor back up & see.

Will purchase an HDMI cable that supports 4K @ 144hz for mac & see if that solves the issue. I had a new HDMI cable anyhow, but not sure if it's that high of quality.

Wish me luck!

I've been getting the same issue with an M4 and LG 32" monitor. In fact there's another topic regarding this issue. From the info in the other topic it's not system, cable or monitor related. It appears it's a hardware issue, with M2, M4 and, I believe, M1 Minis experiencing the same problem.

All we can do is report the problem at the Apple Mac Minifeedback page: Mac Mini Feedback.  

To all:

According to this topic: Mac mini running macOS Sequoia 15.5 experiencing brief 2 second blackouts, if you have the Zoom app installed removing it and all supporting files fixes the problem. I removed Zoom early yesterday and haven't had an outage since.

I exclusively use a Belkin UltraHD High-Speed 8K/4K HDMI 2.1 cable from my M4 Mac Mini Pro to an LG 32UN880-B 4K UltraFine display without any issues.

How long is that USB-C cable run to your LG display? Good luck with LG support.

As hcsitas has already suggested do not put the Mini to sleep. Just use the screen saver and have it go to black after a preset time:

Also if your local power lines are above ground or you experience frequent unplanned power outages I would not have the Mini automatically reboot after a power failure.

As a test

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the Mac Mini On and only allow the display(s) to turn Off

Do not manually Sleep from the Apple Drop Down menu

Shut Down the Mac when away for a day or more

den.thed wrote:

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the Mac Mini On and only allow the display(s) to turn Off

Do not manually Sleep from the Apple Drop Down menu

Shut Down the Mac when away for a day or more

Try the settings exactly as shown below (reboot after changing), should fix.

Also, do not manual Sleep, shut for long absences and let the display switch off on timer during normal use:

(or use Control-Command-Q to immediately lock your screen).

Spoke to APPLE. No solution. Ate the $$$ for the 4k monitor.

Awaiting a solid 2k monitor to arrive. :!

Still hoping for a solution. The KTC monitor was pretty awesome. :!

My LG display is set to go into deep sleep after I power down the M4 mini each night. But, if it does go into deep sleep during the day after the screen saver times out, just a mouse or keyboard touch wakes it up again.

Same issue. I’m using Dell us3223qe monitor. It was working fine for a bit but increasingly unpredictable and now restarting Mac doesn’t even work. Monitor reacts at first but never gets signal and goes to sleep. Have done all the settings ideas noted in this thread. Very frustrating. Yes hdmi would work but this should too, it’s basic functionality touted by both monitor and Mac sales pitch.