New Mac mini M2 Pro "Kills" My Monitors

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New Mac mini M2 Pro "Kills" My Monitors

I have a new Mac Mini M2 Pro connected to two Dell U2722DE monitors via USB-C cables.

Everything worked as expected for almost a week and then suddenly the monitors would not wake up from sleep. Moving the mouse, keys on the keyboard, swiping on the trackpad, no avail. Forcing the Mac to shut down and restarting it didn't help either.

Both monitors however did come alive when the same Mac was connected via a HDMI cable, also when connecting a PC using DP cables. After having tried a lot of different approaches, I just switched everything off (actually pulled the common power strip cord out of the wall socket) for about 30 minutes, connected the monitors to the Mac with the USB-C cables as before and restarted everything. Now everything worked fine again!

Another few days went by with everything working fine and then only one of the monitors went dead; the other one continued working fine but the Mac was only detecting that one. Benefitting from my first experience, I again switched everything off, waited for a while and switched it all back on. Again, everything went back to normal.

Since then, every few days, one of the monitors (not always the same one) goes unrecognized and my switching everything off and on again returns the situation to normal.

Any ideas as to why this is happening?

Mac mini (2023 with M2 Pro)

Posted on Feb 15, 2023 4:00 AM

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Answer 1

Top-ranking reply

hcsitas

Level 6

12,686 points

Feb 16, 2023 9:14 AM in response to Jerry_D

Sleep isn’t necessary for later Macs. Shut for long absences/overnights and turn the monitor off on timer. If you need precise settings, do post. Separately, avoid directly connecting monitors over USB C, they start charging the mini, clueless that the mini doesn’t require charging. Use HDMI+DP.

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Answer 2

Grace2211

Community Specialist

Feb 16, 2023 8:54 AM in response to Jerry_D

Greetings Jerry_D,

We'd like to provide you with a few steps that can assist you with connecting your displays to your Mac mini:

following configurations:

"For Mac mini with Apple M2 Pro, you can connect up to three external displays in the following configurations:

• Connect one external display with up to 8K resolution at 60 Hz using the HDMI port.

• Connect one display with up to 4K resolution at 60 Hz using the HDMI port and up to two external displays with up to 6K resolution at 60 Hz using the Thunderbolt ports.

• Connect one external display with up to 4K resolution at 240 Hz using the HDMI port.

• Connect one display with up to 4K resolutions at 144 Hz using the HDMI port and one external display with up to 6K resolution at 60 Hz using the Thunderbolt ports.

If you’re not sure how many external displays your Mac mini supports, check your Technical Specifications. Open System Settings, choose Help > Mac mini Specifications, then locate Video Support (you may need to scroll).

Note: When connecting multiple displays, connect the display with the highest resolution first."

More details here: Connect a display to Mac mini

We'd also like to provide you with a resource that provide you with a few steps that may help resolve the issue: If your external display is dark or low resolution

Best regards.

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Answer 3

Jerry_D Author

Level 1

30 points

Feb 16, 2023 11:06 AM in response to hcsitas

Thanks a lot, hcsitas. I was wondering myself about the power supply on the monitor's USB C but was thinking that since no consumer is found on the other end, the monitor's firmware would take care of not supplying any power. Now I see that that might not be the case and I'm wondering if that "unresponded" power offer isn't going to harm the monitors (and/or the Mini).

I was already connecting two different computers to these two monitors, and the USB C connectors were the only ones unused - therefore the obvious choice for the third machine (the Mac Mini). Changing this setup is not straightforward since my other two machines don't offer many choices. Probably I'll be forced to remove one of the original computers.

Thanks again for your kind help.

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Answer 4

hcsitas

Level 6

12,686 points

Feb 16, 2023 11:40 AM in response to Jerry_D

You’re welcome, good decision!

FWIW, the earliest USB C model (2018) had assorted complaints of Mac USB C ports going dead/becoming unstable over time when connected directly to clueless, juice-happy Dell USB C monitors. Apple appears to have since fixed the firmware to prevent USB C monitors from messing Mac ports up completely.

However, no monitor manufacturer is interested in interworking with Macs over USB C to perfection. In fact, Dell outright refuses to support any and all Apple connectivity problems.

As a result, mystery problems continue with the user left no recourse other than to abandon the configuration or grudgingly tolerate its limitations.

That’s not to say all 3rd party monitors are unsuited for Macs, just those touting USB C, best avoided IMO. 😉🍻

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Answer 5

Jerry_D Author

Level 1

30 points

Mar 15, 2023 8:45 AM in response to Jerry_D

I might have discovered the root cause. I was using the DDPM (Dell Display and Peripheral Manager - latest version available at the Dell site) that was running in the background. I have killed that app and also removed it from the Open at Login list. Almost two weeks of heavy use later and with both USB+HDMI and USB+USB connections, after many wake-ups from sleep and also a few MacOS restarts, not a single incident! Both monitors work and wake up as expected, also no flickering.

Then yesterday, I started the DDPM app again and sure enough, this morning only one of the monitors woke up while the other required pulling out of the power cord and plugging it back in, in order to start working again.

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Answer 6

Jerry_D Author

Level 1

30 points

Feb 16, 2023 10:49 AM in response to Grace2211

Thank you, Grace2211, but your kind response does not address my question. Thanks anyway.

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New Mac mini M2 Pro "Kills" My Monitors

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