2018 Mac Mini - monitor problems

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.

This started happening for me immediately after the supplemental 10.14.6 update in October 2019, and continued into Catalina. As I've had FileVault active since I got my 2018 Mac mini in December 2018, I'm not sure how I escaped this issue's effects for most of 2019. And, alas, that it showed up on a system update rather than at the time I enabled FileVault meant that it took me quite some time to discover it was FileVault related.

Anyway, confirming:

• It is FileVault related
• If my display is sleeping, I need to wake it before turning on my Mac mini, then I will reliably get the video signal

Just a heads up that I made at least one chat and two support calls and two Genius Bar appointments about this and nobody was cued to ask me "Do you have FileVault enabled? Oh yeah, you have to turn your display on before the computer" This resulted in my spending somewhere between 10 and 50 hours trying to track down the cause of the behavior as well as using up their support time trying to find out what was going on.

Given that it started happening with a software update, I'm guessing it is software-related.

I'm happy to be able to use my computer once again after a month or two of dealing with this, and happy that the solution is so simple. Given that a post in this thread says it's a known issue, it's frustrating that it's not part of the troubleshooting procedure for phone support.

At the same time, it's interesting that my startup procedures are so standardized, and I was so focused on trying to document the steps I was taking for the support line and Genius Bar appointments (I normally let my monitor go into power-saver mode rather than turning it off) that I never randomly discovered the workaround or connected that the occasional successful boot-up was actually the work-around in action and not that - my incorrect conclusion - it was an intermittent problem. *sigh*

I had problems with three LG 27UK650-W monitors attached to a Mac Mini (2018). When resuming from sleep it would usually lose the HDMI connected one, but could lose other monitors as well. I had boot up problems with totally blank screens as well. Disabling FileVault fixed these issues.

Good news everyone.

first, my mini i7 2018 8 GB memory 1 GB Ethernet has every problem listed in this discussion. Dual monitor ****. FileVault failures. USB overload. Monitors blinking out randomly. Same issues persisting from 10.14 through 10.14.5

Finally, word was blinking out when under heavy load.

this was the last straw. I complained to Apple over the phone.

This mini was absolutely not reliable.

Here is is the good news.

i discovered the fan was not working. I took it to the Apple store. Check yours with restart+D to do a hardware check. I got error message 003 confirming the fan was bad (not spinning) and that leads to setting up an appointment at the Apple Genius Bar. They replaced the fan and motherboard. No charge for

labor or parts, all done under warranty.

Now, after 36 hours of heavy usage with 2 monitors, everything is working well. Monitors consistently start up from sleep or restart. FileVault works again. I am using the same monitors and cables that were failing so often on the original mini.

conclusion. I think my motherboard was bad. This is a possibility for everyone with these issues. The answer is to get Apple to replace the motherboard.

I believe I have found a workaround in my case.

I have a Acer Predator XB271HU 27" monitor that I'm using with my new 2018 Mac mini. Regardless if it was connected via USB-C to DisplayPort, or HDMI it would not reliably display video after restarts, shut downs, and sleeps just like everyone has been reporting.

In my monitor's control panel I disabled an option called Deep Sleep. Doing this, plus running the monitor at 60Hz only (the monitor supports 144Hz+) seems to have corrected the issue for me. It works fine regardless if it's connected via DisplayPort or HDMI now. I have tried multiple reboot, sleep, and shutdown cycles and haven't been able to make it fail.

If you have a similar option to Deep Sleep you can disable in your monitor I would recommend giving it a try, and also ensure you are running your monitor at 60Hz only.

Thanks so much Rayluca2! Yes the 10.14.6 beta has cured the issues for me as well.

I was able to re-enable Deep Sleep mode on my monitor. I can startup, restart, sleep, wake from sleep, and enter recovery mode with no issues regardless if I'm using HDMI to HDMI or USB-C to DisplayPort. This is all at 60Hz which is as advertised. If I try to run above 60Hz things get dicey again, but this is fine.

I'm sorry drifter7508 you are not having the same luck. You might want to try clearing the PRAM and SMC after installing the latest beta of 10.14.6 if you haven't already.

https://support.apple.com/en-us/HT204063

https://support.apple.com/en-us/HT201295

I've had these same issues where my display goes black on boot, lockscreen, or sleep and tried other solutions as noted on this thread, such as swapping out cables, using different ports, not turning off Mac Mini, etc. My problem with the display going black (no signal) was so SEVERE that I was seriously going to buy a new monitor or return my Mac Mini and get a Macbook laptop instead. Trying a new monitor was not an option for me, I don't have the funds right now to go buy a new gaming monitor. Especially after my new Mac Mini purchase in May 2019 and new monitor Samsung C32HG70. Any extra old monitors that I had laying around my house were given to friends last year so I didn't have available test bench equipment.

Hardware I'm using:

Samsung C32HG70 32-inch HDR QLED Quantum Dot Curved Gaming Monitor (144Hz / 1ms) Model C32HG70QQN

https://www.amazon.com/dp/B06XT6WQCJ/?coliid=I1VUC0FZY8WHCW&colid=FJKVUTS6GSEI&psc=1&ref_=lv_ov_lig_dp_it

This is a newer monitor model that I purchased from Amazon and had great reviews. I use my Mac Mini mostly for YouTube and gaming using Parsec (where I remote access my Windows 10 gaming rig in my house).

My Mac Mini 2018 hardware:

Hardware Overview:

Model Name: Mac mini

Model Identifier: Macmini8,1

Processor Name: Intel Core i7

Processor Speed: 3.2 GHz

Number of Processors: 1

Total Number of Cores: 6

L2 Cache (per Core): 256 KB

L3 Cache: 12 MB

Hyper-Threading Technology: Enabled

Memory: 32 GB

Boot ROM Version: 996.0.0.0.0 (iBridge: 17.16.10482.5.10,0)

Activation Lock Status: Enabled

Another forum member suggested to download the new MacOS, and I would like to give a huge THANK YOU to whoever that was. The only solution that is worked for me so far is to enroll in the beta program and download the new Catalina (beta) MacOS. In my opinion this is either a driver problem or firmware update that Apple did with the new MacOS. I downloaded Catalina (beta) 3 days ago and tried to replicate my screen issue and the good news is I have not been able to break anything.

When I power on my 2018 Mac Mini with new Catalina OS, there seems to be a new screen refresh with Catalina right before you see your login prompt.

This screen refresh, whatever is doing behind the scenes, seems to have corrected this issue. Even though 3 days with my new OS is a small sample size, I've done a lot of testing and no new instances of no signal black display issues with my monitor have occurred.

I recommend that for anyone having display issues where monitor goes black (no signal) with their 2018 Mac Mini to upgrade immediately to beta Catalina MacOS. This is a free upgrade, you only have to enroll in the Beta program with Apple. Just make sure that you backup any important data that you have before you upgrade just in case things go south. I have another computer that hosts my critical data, so I upgraded without much hesitation.

My current OS version:

10.15 Beta

Link for beta program:

https://beta.apple.com/sp/betaprogram/redemption#macos

I have been using HDMI + USB3/miniport and that worked with 2xLG24UD58 in 95% of all boots. I did that because 2xUSB3/miniport worked in less than 10% of all boots. I have now updated Mac Mojave release 6 (10.14.6) and I am happy to report that it looks like that fixed it (as was in the release notes). I can connect both monitors on USB3/miniport and booted twice with no problem. Of course the proof is in the pudding so the next few days will show if it works in all conditions but so far, I am a happy camper !

Interestingly I was having this problem until I realised if I switch on my Mac Mini before turning on my monitor the mac mini refuses to detect the screen unless I power cycle it. However if I make sure my monitor is on (showing no signal or similar and not in standby) before I turn on the mac mini when its powered on screen works straight away. I've been shutting my mac down and turning on daily and the screen has consistently been detected. I'm using Thunderbolt 3 connections to a 4k screen

I admit it shouldn't be this way and the mini should detect the screen even after its been switched on but at least it works as intended! Running 10.14.6 Mojave. Hope this helps someone!

I have a Mac Mini (2018), and as soon as I changed to a usb-c <--> usb-c cable that came with the 27" LG all was well.

The time for the wake up from sleep seems to vary from "right now" to "ah, give me a few more seconds," but not really a problem. FileVault is enabled, and boot up from cold, from restart, and from OS updates seems normal. Screen resolution OK.

I found a hardware workaround for my case. I have a couple home theater HDMI man-in-the-middle adapters for manipulating EDID and splitting audio. The first one I tried is the Gefen HDMI Detective Plus. This did not work for me even with the computer booted, but it was likely due to misconfiguration. The second device I tried is a ViewHD HDMI audio splitter (v1.3). This worked immediately and I get the Apple logo when I power up, and the FileVault login appears on screen. I'm not sure, but I think this device may defeat HDCP between the monitor and the adapter, and that could have something to do with the fix.

As far as I know, the Mini does not support HDMI audio, but this device has a pass-through mode which I enabled anyway.

Note that these are 1080P adapters. There are other models which support 4K. I don't know if these work with the Mini or not; I just wanted to share my personal success in case this helps someone.

I just got my first Mac Mini/Mac Desktop and i'm having the same issues with 4K monitors. After messing with settings and finding out that something is keeping the video card from running, so i decided to turn off FileValut. Reason why did that because it seemed weird the monitors wouldn't come on, but when i first set it up the MacMini and rebooted a few times it worked perfectly. The only thing i did after setting it up was enabled FileVault. So i powered on my Mac and waited a 30 seconds then clicked my mouse and type in my password like i always do on my MBP. That worked and i was able to see it fire up and my displays worked.

So disabling FileFault is what I did but its for sure not the most ideal fix. I would love to have my hard drive encrypted, but it resolved it for me for now. Guess i'll have to use another way to encrypt the hard drive to see if that breaks it as well. Thought i would share that with anyone that is wanting to test it out.

Yes, at this point everyone but Apple knows FileVault is the issue. The window that appears when FileVault asks to unlock the disk does not wake up some modern monitors.

Everyone but Apple seems to know this now.

For some of us, disabling FileVault is not an option.

I, for one, am hoping Apple ever-so-slowly fixes this, but I'm starting to lose hope that they are competent enough to care.

I'm having issues also - I have 2 new LG 4K screens and 1 old crap Dell that I rotate and use for long lists (for example) that don't change much.

NONE of the 3 displays worked. It seemed that nothing I did would change anything and I was pulling my hair out! And no, it's not FileVault; there are too many inconsistencies in the reports, and there are too many having trouble who don't use FileVault at all. But guys - the answer is not to immediately throw tomatoes at Apple, say that they suck, it's all their fault, that quality control is down, take it back to the store, yell at people on the phone, etc. Please, put your torches and pitchforks away for a moment.

I needed to have some patience. Like some of you I stripped it down and started with one display at a time, with just the Mini (I had also bought the BlackMagic eGPU). What you need to do next is not to add a second, and then the third; it's to do one display again - a different one. Use the same cables you used for the first display, if you got that one working. Then the third one by itself. Doing this I discovered that each of my screens worked just fine with my new Mini. And I also learned that those particular cables were good. Now I was feeling a bit relieved, because I was beginning to think that I had made a mistake in buying everything that I did.

Looking at Apple's instructions, it seems that the best way to attach my particular displays is via DisplayPort for the 4K screens, and HDMI for the crappy Dell. And so I connected the Dell - with a DVI to HDMI adapter - to the Mini and got...nothing. No worries - no need to reboot, reinstall, zap the VRAM, etc. I just messed with the cable and the adapter a bit and lo and behold, a picture appeared! It would seem that I might have a bad cable. Now I'd add in more - the eGPU, with a thunderbolt cable. Tried to use the HDMI port there instead of the Mini. Also tried the second display by DisplayPort to thunderbolt on there. No joy. Sure, I was frustrated...but not yet time to develop a hate-on for Apple. I looked around and found the thunderbolt cable that came with the GPU (I was using another cable instead because it was longer). Replaced the cable - and both screens now worked.

I still haven't got the third display up and running...but I'm sure I will. I don't have a signal, but I have power to it now - because it needed to be moved from one outlet to another in the UPS (sheesh!). And I'm not saying that there isn't an issue - I believe there is something strange going on. But I also believe too many were too quick to jump on the "They Suck! Kill Apple!" bandwagon. Spend a little time with your Mini, guys - make sure there aren't any bad cables, adapters, outlets, or configurations. Maybe some patient troubleshooting will help a few of you? I hope so. Good luck with everything.

I found my solution which happens to be the same as a couple of others who wrote on here.

Hdmi > hdmi cable DOESNT work

USB-C > hdmi WORKED

For those wondering, the cable I bout was Uni USB C to HDMI Cable(4K@60Hz). Its on Amazon for $20. I hope this helps some people.

Im running dual monitor set up. One is an old Acer (no problems usb-c to DVI) the second (one that had problems initially) is AW34DW Alienware ultrawide. All seems right now.

This unfortunately still means that the 2018 Mac Mini's HDMI port is shot. Or just doesnt function correctly. Since it was having no issues previously with my iMac 2013.