2018 Mac Mini - monitor problems

Since 10.14.5 I no longer have any problems. The monitor comes up quickly

Since 10.14.6 was released it appears my monitor problems were solved.

10.14.6 supplemental update (released today) may help. The result should be 10.14.6 (18G87). If it still shows 18G84, install it again.

I had the same problem with my mac mini with lg 27ud58-b. Bought usb c to hdmi did not work.

I did pram reset on my mac and the monitor worked fine after that.

Just updated MacOS (Catalina 12/10/19)) on my Mini. Monitor now works as expected. Previously I had to restart the monitor whenever waking the Mini (No connection). FWIW, file vault is off.

The final release of 10.15.4 is out, and it does not solve the issue. The hardware workaround (HDMI audio insertion device) still works. Very disappointing.

I had a very similar issue. Plugging my 4K monitor into the HDMI output of the Mac Mini wouldn’t work (no display).I tried to connect it to the USB c using an HDMI adapter and that solved it.

When using the HDMI output of the Mac Mini display would work when using both the 4K screen and a second monitor plugged in. Apple support was no help.

I also noticed that the windowserver.plist files would not update when using the HDMI output. That also went away when I started using the USB c... Very frustrating and strange.

My only issue now is that the display wakes up on a delay, also strange and frustrating.....

Update

I've connect mac mini to TV via HDMI + LG 24UD58 via USB-C -> DP and it works!

If i change TV to my old 1080p display (hdmi->dvi) - LG 24UD58 via USB-C -> DP do not work.

So, i suggest, mac mini needs any correct hdmi connection to work with DP.

The “fix” is not using FileVault, or waiting for a firmware update. Try using Apple's Feedback system, and if you have a developer account, file a bug report.

We really need more people to provide the feedback so they'll do a firmware update, which is the only way it can be fixed.

I just got mine working with usb to hdmi male cable and an adapter DVI on monitor to hdmi female! (2) bi-directional Adapter 6.99 on amazon and cord 12.99

taking back 2 35.00 cords to store for refund that did not work!!! The cords and or adapter should be sold as part of the **** computer it will not work without proper power supply! Now monitor comes on when computer comes on!!

There have been a few issues mentioned on this thread.

I have the mini connected to a single new LG 4K monitor. It used to have issues waking up. But yes, the new software update found here: http://beta.apple.com, fixed my problem completely. I cannot speak to the other issues people have regarding dual monitor issues, etc. But yes, my problem has been resolved.

I think the last few pages of discussion have shown my issue. I have an LD monitor with HDMI 1.2, not 2.0. It is incompatible with startup for the Mac Mini 8,1 and probably always will be. (It's a $340 monitor so I'm not happy about possibly junking it.)

Apple does say right up front that they only support Thunderbolt 3 or HDMI 2.0. Well, they don't really say that they won't take HDMI 1.2 or Thunderbolt-to-DisplayPort, but they also don't say they will!

They do say that their own TB3 to DVI should work, but the monitor only takes DisplayPort and HDMI 1.2, so that doesn't help.

I can, if I rearrange cables, start up with my old HD Spectre, running from the HDMI port into a DVI adapter (I don't think it works if I just connect via HDMI but will try that next). That works, then I connect the LG 34UD HDMI 1.2 to a TB3-to-HDMI adapter.

Realizing that HDMI 1.2 is not supported (and probably never will be) is essentially the end of this, I hope. I still sometimes have the no-monitor-on-return-from-sleep issue. Going back to sleep and waking up again works to solve this.

Not really plug and play or “it just works,” but Apple hasn’t promised either of those in quite a few years. I guess it looks good and it's thin, and that's what really matters, right? I do like the speed, and waiting for the new Mac Pro wouldn't really have gotten me anything.

I think I have got a workaround. At least in my case it has worked. I have an LG monitor and as everybody I am experiencing problems when booting my Mac mini 2018. It appears the apple and the bar and when at the middle it vanishes and appears a message "No signal". I usually switch off the display and switch on again, and it works. However, it is a temporary solution.

However, this morning I tried something different. Apple/around this Mac/display and open preferences. There if you push Alt key it appear "Detect display" push it twice. The next time you boot the Mac mini it will detect the HDMI and there will be no problems. At least it happens to me.

It seems that Mojave requires confirmation of the display although it is detected through HDMI.

This is clearly a bug.

Finally, the other day an engineer of Apple send a message asking me to take a picture to check how I have plugged the HDMI cable to the Mac mini. It seemed so stupid to me that I have presented another complaint against Apple Spain.

Well I share this solution with you and hope it works.

I received from eBay USB-C to HDMI (male) adapter. I'm testing it almost one week and till now I have no problem. I'm curious what will be with the next OS update. Now I'm running at 10.14.5.

Monitor LG W2600H DVI to HDMI cable connected to MacMini 2018 via USB-C to HDMI. As I mentioned here, the DVI to HDMI-HDMI(MacMini) causing problems.

Good luck to every one. Hope that apple will solve it.

There does not seem to be an Apple fix, so I am using this work-around:

Think server + dumb terminal. When I worked in IT the server was on 24/7 and dumb terminal, etc were connected & lit as needed.

My Mac Mini 2018 is now on 24/7 with no need to wake-y, wake-y.

(1) System Pref --> Energy Saver

• Turn display off after-->Never
• Check prevent sleeping... All other boxes off

(2) System Pref-->General-->Check Require Password & set time (I use 5 min)

If leaving the active computer for a while you can log out or sleep the screen with the mouse pointer and system times out to require log on.

For longer periods, I log out, and turn off the LG monitor. (Déjà vu my main-frame days...)