External display doesn't wake up in Mac Mini 2018

Question

Level 1

19 points

External display doesn't wake up in Mac Mini 2018

Hello, I had been using a 4k external display (BenQ EL2870U) in my Mac Mini 2018 since I bought it last December with Mojave with no issues. I have recently upgraded to macOS Catalina and since them most of the times when the screen goes to sleep it doesn't wake up anymore. The only solution is to manually reboot the computer and then the screen is detected again.

Using Screens I have connected to the Mac mini while having this issue and open the display properties in the configuration and curiously it says that my screen is Retina Integrated Display (which is funny for a Mac mini)

I tried to unplug the screen from power, to unplug the HDMI, to change resolution but it doesn't change anything, it's like when the screen goes to sleep it is not detected anymore by the computer.

I have seen some people reporting this problem with Macbook Pros and iMacs, but nobody in a Mac mini, an indeed no solution has been proposed. That's why I open again this question.

Any ideas?

Posted on Dec 9, 2019 9:25 AM

Reply

Answer 1

Best reply

karioko Author

Level 1

19 points

Dec 15, 2019 10:46 AM in response to hcsitas

Thanks everybody for your answers trying to support me. Indeed I already tried with different cables (for instance the same one I'm using for connecting my AppleTV4k with Dolby Vision for my TV) and the problem was existing anyway. And for me the issue was in the OS as it was working fine until I upgraded to macOS Catalina.

Finally last Friday I decided to do a clean install of Catalina, and since them the problem didn't appeared again in the whole weekend so I can almost confirm it has been solved.

Reply

Answer 2

hcsitas

Level 6

11,390 points

Dec 9, 2019 12:02 PM in response to karioko

Has to do with cable and/or monitor settings, start by checking/setting:

Cable - use length preferably not longer than 3 feet
Picture Mode Standard or M-book
Super Resolution Off
Auto power off OFF

If that doesn’t work, please post a screenshot of your macOS display settings. Good luck.

Reply

Answer 3

dwb

Level 7

32,920 points

Dec 9, 2019 11:10 AM in response to karioko

I think you display supports both HDMI and DisplayPort. There are certainly a lot of people who have reported issues with the mini and HDMI - I've experienced it myself. Personally, having experienced a goodly amount of HDMI craziness with my TV and peripherals, I wonder if it is cable related. Then again my problem with my mini and HDMI involved a high quality cable so... This is a long winded way of saying DisplayPort problems seem to be reported much less frequently and for the short time I couldn't get my computer and display to speak via HDMI, DP worked just fine.

Reply

External display doesn't wake up in Mac Mini 2018

Similar questions