Mac Mini and LG 4K Monitor Prob - SOLVED!!!

[yukari]

So like many of you, I was having problems starting up my 2018 Mini connected to LG 4K monitor via HDMI. The monitor would be black on start up and sometimes had to unplug and replug to get to the log in screen.

I got tired of this and started to dig around LG Monitor manual and this is what I found...

As you can see, if you have a trouble not seeing a signal come through they suggest turning off "HDMI ULTRA HD Deep Color". On my LG, it is under "Settings"-->"Pictures" (NOT General settings).

When I turned off this "HDMI ULTRA HD Deep Color", voila! It worked. Now I get the log in screen when I turn on my Mac Mini.

So check your monitor for a similar settings.

I hope this helps at least some of you.

 

[Ign1stra]

I also had this problems in the past with the 4k LG Monitor and I found this solution too. The problem is, when you disable the "HDMI ULTRA HD Deep Color" option the monitor outputs only a picture with 30Hz instead of 60Hz which is in my opinion not a good solution.

In my case, I have solved this problem now (with enabled "HDMI ULTRA Deep Color" option) with connecting the LG Monitor over an eGPU.
Thunderbolt to eGPU -> Displayport to LG monitor.

 

[yukari]

Yes you are correct.
but I don’t play any games or videos much. Most of my work uses MS Office suites progs and some web surfing.

And I didn’t want to spend another $500 + for eGPU.

 

[jayducharme]

Another option, as I mentioned in another thread, is to get the Moshi USB-C-to-DisplayPort cable. It outputs full 4k at 60 hz to the LG with no problem.