M1 Mac Mini still doesn't wake external monitor

I've got a 2021 Mac Mini attached to an LG HDR 4K 27" display, connected via Thunderbolt. I leave it on and running, and when I tap the keyboard and/or mouse to wake it, most of the time it works fine.


However, every few days (too often to make this not annoying) it refuses to wake the display. I have to unplug the Thunderbolt cable then plug it back in before it will wake the display. The Mac itself is NOT frozen or having any other problems.


The keyboard/mouse is Logitech Ergo K860 and M525 -- the transponder is plugged into the back of the LG display.


I was hoping this would be resolved with Monterey, but it hasn't been (I am on 12.0.1 and still having the problem).

Yes, I have indeed reset the PRAM/NVRAM, etc.

Mac mini, macOS 12.0

Posted on Nov 7, 2021 3:59 PM

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16 replies

Dec 1, 2021 9:01 PM in response to hcsitas

Okay, so after adding an HDMI cable to the Mini and using it for a couple of weeks, I've found that it works just perfectly. I can eliminate the Logi Receiver as the problem (phew -- I love the ergonomics of the Logi keyboard).


The problem is that when only connected to the external display via Thunderbolt, the M1 Mac Mini will sporadically refuse to wake up the external display. The Mini itself has not crashed, and unplugging/plugging in the Thunderbolt cable to the back of the Mini will wake the external display correctly.


The downside is that this shouldn't happen -- if Thunderbolt is supposed to carry everything, then it should work. I shouldn't need the HDMI cable in addition to the Thunderbolt.


Also, now my Displays preference pane thinks there are two displays attached: one via Thunderbolt, and another via HDMI, so I'm permanently now mirroring the display to the two interfaces.


This is some Windows Vista kind of junk.

Jan 10, 2022 3:47 PM in response to PugvE

BTW, another piece of datum.

This problem doesn’t exist when I connect via Thunderbolt to a 12 year old Dell monitor. I used this monitor for the 4 months I was working with LG……with NO issues, not once.

I believe this is an Apple/LG communications issue. Ran into something similar with new TV from LG…..they changed their internal program and never communicated change with outside vendors like BOSE so BOSE wouldn’t work properly until the two companies got together to resolve the communications issue.

Jan 11, 2022 7:32 AM in response to PugvE

Unfortunately, my attempt to solve with hdmi cable failed. Could not get LG monitor to display with old cable, new hdmi cable, by unplugging Thunderbolt etc.

So to confirm mini was “ok”, I plugged in my 12 year old monitor into the mini while mini was “on”…….and bingo, old monitor displays perfectly.

The LG is going back to Apple

Jan 10, 2022 3:42 PM in response to jeepish42

I agree with your issue as described. I’ve had same issue with 2 LG27 monitors. Apple denied it was their issue even though they sold the unit so I was forced to work with LG which took 4 months and three returns for repair before LG finally refunded my purchase……purchased second one in December 2021 from Apple. Worked for less then 2 weeks then the same thing started.

I disagree that switching to HDMI is an acceptable solution…..it fix’s it but should not be required, just like changing settings to prevent sleeping is unacceptable.


I will try the HDMI solution because the monitor image is flawless and worth the effort but not happy.

Nov 18, 2021 10:48 AM in response to hcsitas

Okay, I unchecked "Wake..." and waited. After a few days, same problem persisted: had to unplug and re-plug in the external monitor via Thunderbolt before it would turn on. The Mini was awake and working fine, but just won't wake up the monitor.


At this point, I've tried:


  • Logitech receiver plugged into the monitor and into the Mini directly -- problem persists
  • Prevent Mini from sleeping when display is off -- problem persists
  • Wake for Network Access on, and off -- problem persists


I've isolated each one of those settings and used the Mini normally, and let it sit a few days each time. For each variable I tested, the problem recurred after a few days: the external monitor simply will not wake up.


The next thing I'm going to try is using HDMI to connect between the Mini and the display. I hate going that route because it's adding another cable to the mess -- the Thunderbolt connection should be all I need.


Jan 11, 2022 9:57 AM in response to jeepish42

My 16 GB M1 Mac mini is attached to 3 monitors in a flight simulator. Two of the monitors come on immediately when the computer is started. The third one hesitates, but always comes on in less than a minute, with no further action on my part. It is as though the computer and monitors need to figure out which is boss.


Try a little patience. The computer has artificial intelligence, and may not like being treated like an adding machine.

Jan 11, 2022 1:29 PM in response to PugvE

No. The 16GB M1 Mac mini is connected to:

(1) To a Dell model 2007 FPS monitor (1600 x 1200 @ 60 Hz via VGA on monitor to VGA/DVI-I adapter to Startech.com USB 3.0 Dual Head Graphics Adapter to USB-C on Mac Mini).  DisplayLink driver from startech.com was loaded and activated.

(2) to a Westinghouse TV model LDD2240 (1920 x 1080 @ 60 Hz via HDMI to HDMI).

(3) to a Flatron W2252TQ (VGA ơn monitor to Belkin VGA/Thunderbolt adapter to Thunderbolt on Mac Mini). 


My reason for joining this thread was because the three monitors do not all start up simultaneously, but all three do come on in about a minute, with no further action on my part.  My point was that you might have to wait a moment before all of your monitors “kick in”.

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M1 Mac Mini still doesn't wake external monitor

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