2018 Mac Mini - monitor problems

I have a new 2018 Mac Mini (running OS 10.14.2) which is connected to a LG 24UD58 monitor via a USB3 to DisplayPort cable.

When I shut down the Mac and then try to start it up again, the monitor is blank and does not appear to be receiving a signal from the Mac. I had the same problem when using another monitor (my old Dell U2312HM) using the DisplayPort cable.

When I connect both monitors (the LG via Display Port; the Dell via an HDMI), I am able to shut the Mac down and then start it up again, with both monitors working.

There are other users with similar problems.

Is there any fix?

many thanks

Mac mini 2018 or later

Posted on Dec 21, 2018 10:12 AM

Top-ranking reply

FLUXFAZE

Level 1

13 points

Posted on Sep 29, 2019 8:04 AM

The Mojave 10.14.6 update appears to have resolved the issue for me. Before the update, I sometimes (but not always) had to press the power button on the Mac Mini (i7 16G 1TB) a couple of times (one press for 1 second & release, then a quick second press & release) before the Mac would recognize the monitor (an LG 34" HDMI connected). After the 10.14.6 update I haven't had to go through that rigamarole again. The Mac is recognizing it every time now as it should.

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455 replies

aon189

Level 1

4 points

Oct 17, 2019 11:07 AM in response to Davert

Seems to be running perfectly for me again using a usb-c to HDMI cable, just got one today. 4k Samsung monitor.

den2020

Level 1

4 points

Oct 17, 2019 11:49 AM in response to robby163

Well I don’t have a LG monitor. Mine is a Samsung and a Dell. Also I have the latest/last Mojave OS. No dice. Doesn’t work.

Jary322

Level 1

4 points

Oct 18, 2019 4:04 PM in response to meng187

Thank you @Meng!! It worked! With both!

usb-c <--> DP

usb-c <--> HDMI

LG 27UK650-W

THIS SETUP BELOW DID NOT WORK POST CATALINA UPDATE

HDMI <--> HDMI

ciuchka

Level 1

4 points

Oct 24, 2019 7:58 PM in response to wingbui

This worked for me: 4k, 60hz USB-C cable in the MacMini, and HDMI in the LG 27UD58.

cpmax

Level 1

14 points

Jan 30, 2020 3:53 PM in response to NoQuarterTech

Can you verify if you're USB-C to HDMI adapter connected monitor is running at 60Hz? Do a Apple -> About This Mac -> System Report -> Graphics/Displays

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2018 Mac Mini - monitor problems