2018 Mac Mini - monitor problems

I concur. I bought new monitors, new usbc to display port plugs... all to no use.

most of the times when Mac mini 10.14.3 512 gb, external thunder bay box with jbod, wakes up from sleep, one or the second monitors is blank. Juggling between usBC and hdmi ports does not name a difference. Option command p r restarts does not make a difference,

only cure seems to work... remove the usBC to dp plug, then replug.... then 2 monitors work fine until the next sleep or restart.

monitors: 4K lg 32 inch, Samsung, apple cinema, etc. swapping monitors does not make a difference.

apple... pleas fix this!

I fully agree with the remark that it must the combination of Mac mini 2918 and LG. I tried several LG monitors all with the same results. "No signal, going into standby mode"....

I think that both Mac mini and LG need to update their firmware to get things up and running again.

Gmac34 and Davert - I don't mean to imply that it's something simple and that nobody tried jiggling a cable. :) There are all kinds of users on here, and many who may not be as tech-savvy as you and I are. For some, it IS a simple case of changing the cable, etc.

I don't think there has been an "official response" from Apple because there isn't an official problem. At least, not a reproducible one. I sought out answers, like you, when I couldn't get ANYTHING to work properly. Now I've got all three of my screens working (1 old HD Dell rotated 90° and 2 new LG 27" 4Ks), as well as a USB 8-bay RAID, two 4-bay RAIDs (one thunderbolt, one USB), two 8TB drives, an old JBL "Creature" sound system (anyone remember those?), and a USB 3.0 hub with a plethora of devices attached including a 3.0 dual-drive dock, an old mic, my UPS, my mouse's charging pad, and my keyboard. Not a hiccup from anything...but it took a lot of frustrating cable-swapping and even outlet-swapping on my UPS.

Perhaps this Mac Mini is significantly more sensitive to sub-par cables, etc. The short cable that came with the BlackMagic eGPU made the biggest difference for me. The cord I had been trying worked just fine for everything else - but not with the eGPU.

I have to disagree that Apple's Quality Control is down; don't forget that Apple used to make EVERYTHING. Each part of the computer was proprietary, from the displays to the graphics cards...even the RAM was Mac-specific. Apple knew everything would work, and quality control was easy with the "made for Mac" peripherals on the market. It's why Windows was a mess and Apple "just worked". But people will always complain, no matter what you give them; at that time they wanted Apple to do away with the proprietary hardware and use standardized parts. We have that now - I can put any drive I want in my Macs, any RAM, GFX cards, etc. And with that freedom to choose comes infinite possible configurations - a quality control nightmare, and unhappy users who want it to "just work" like it used to all those years ago. ;)

thiagodeepcover,

“It's has been 2 weeks since i bought a new Dell monitor and the problem

disappeared. New Dell monitor + Cinema Display working fine and Mac-mini

doing all his functions properly (sleep, start, cold start and so on)”

That's the solution — not using an LG monitor. Unfortunately, I can’t really throw out an almost new $400 LG monitor just because Apple didn’t test their computer sufficiently.

I agree on your diagnosis, especially because the specific problem I am having (monitor lights up, goes into sleep on boot and does not wake up) ONLY occurs when we have a boot-from-hardware-off (not on reboot) and with FileVault on.

Problem: getting Apple to ack. and fix.

After 10.14.5

Before 10.14.5

Let's hope that the firmware updates included in 10.14.5 to the Boot ROM and the T2 Bridge OS have now fixed the failure to wake from sleep monitor issue. Only time will tell...

I bought an i7 16GB 512GB SSD Mac Mini 2018 a couple of months ago, didn't notice any issues at first, i was just setting up, installing software (xcode and android studio) and having a little play... i've only just started using the Mac Mini over the past couple of weeks. Last week it had a file system corruption reported on boot, fixed it and after checking the system, no smart issues and all diags passed... might have been power off related.... the issue i've been noticing the passed week, is the same monitor issue you've all be experiencing.

I'm using just the one monitor, a BENQ BL2710 (2560 x 1440) via the usb-c to displayport . This monitor was used for my Mac Mini 2014 for a few years via displayport with no issues at all. It's the main monitor for my Windows 10 i7 system, and used heavily daily.

The normally process has been as follows, boot, login prompt appears, login, once it gets to about 60% loading, screen goes blank (black), sometimes the monitor says lost signal, i have to power off the monitor and power it on or unplug the USB-C cable and plug it back in for the monitor to show the desktop. Other times, the monitor wakes up on the desktop. Hit and miss which one i get. This is often from a cold boot.. more often than not, rebooting, i'm often left having to touch the off/on monitor button to get the display to show again.

Started noticed on some occasions screen corruption on post boot, only happened a few times, happened about an hour ago.. solution is to power off the monitor and everything displays normally. Even on some occasions, i've had to power down as unplugging the cable or powering off the monitor made no difference.

I noticed the 10.14.5 update, updated and still no change.... so downloaded the latest mojava 10.14.5 from apple store, created a USB installation, wiped the mini, reinstalled.. still no change... I've even turned off FileVault.. makes no difference. Even unplugged he USB-C DisplayPort and switched to a HDMI to HDMI, still screen goes blank. I've tried different USB-C ports.

I've tried the NVRAM/PRAM and SMC options.

Done the factory reset with 10.14.5, changed ports, changed cables... still getting blank screens / loss of / or forced to power off. Even noticed some flickering on the screen, that's rare, it has got my attention.

I was thinking i had a 2018 mini with a corrupt video graphics, i googled and found i'm not alone, it appears quite crowded with this issue. I'm starting to regret upgrading from the 2014 when it worked well, albeit slow.

Yet diags report system is ok.

The new release seems to have fixed my problems. I have a simple one monitor setup. The monitor was blank with the HDMI connection to the mini. I would have to connect the HDMI cable to the USB C hub and then get the image. Even then it would take a while to appear. Now I use the mini's HDMI port and it comes up quickly. So my simple setup appears to be working fine now.

Well, it turns out that my problem is self-inflicted. My HDMI cable was an older, lower bandwidth cord, and when on the phone with Apple Support they suggested I try another. As it turns out I had just been fussing with the Apple TV HDMI cable tests over the weekend and had swapped out a cable on the Apple TV for one that tested OK. Putting the OK cable from the TV into my HDMI-connected monitor setup fixed the random boot failure. I had been thinking about using newer cables for the 4K TV since Apple TV now supports more 4K HDR content, but I wasn't thinking about what a cable bandwidth limitation would do to my computer monitor setup. Thanks to Apple Support for suggesting the fix. My monitor for the record is an NEC PA271Q 2560 x 1440 running in native resolution at 60Hz. Don't know if the mini supports 8-bit 4:4:4 or 4:2:2 or 4:2:0 color, but either ways it's a lot of bandwidth for an older HDMI cable built for 1920 x 1080 30p. Perhaps the OSX update changed the timing of the turning off and on of the switch to log-on screen and the cable caused the monitor to lose lock. Works better now, though.

I have a new LG 4K@60Hz monitor (UL950) connected to a brand new 2018 mini via the LG HDMI cable. Use HDMI on the mini end also. It has been working with no issues all week with full 4 K resolution. (3840 x 2160). Running TB3 had multiple problems, I didn't test the Display Port option.

I'm using USB-C to DisplayPort. Yes it's still working fine so far with normal cold boots, restarts, and wake from sleep. But it doesn't work fine with entering Recovery Mode. I'll have to unplug and re-plug the monitor in when I try to do that. My cable is rated for 4k at 60Hz use. I know some are rated only at 30Hz. I have no idea if that makes any difference really. The Mac mini is still bugged regardless of any tricks done to make it work more reliably.

Just came across this issue now as I had varying peripheral issues from blu ray drives to bluetooth and this! I thought I was going crazy but looks like a lot of people are having this issue - Only way I have managed to solve this is either powering off the mac by the power button or turning the display off and on again. However it is sporadic that these solutions work - Definitely think its related to file vault as when I do get it working I am dropped to a Forgot password screen. I think the disk encryption password prompt is on screen when the display is inactive leading to this issue. I'm going to wait for the release of the OS and hopefully that will resolve the issue

I'm running a 2018 Mac mini (Mojave 10.14.5) and every time it restarts I have to unplug the HDMI cord from the LG monitor - count to 5 and plug back in. I know it's on because when I tap the keys or mouse I can hear the bing from the speaker. Works fine after that even from sleep mode. Only on restart does the monitor show no signal. Thought it was because I bought refurbished. This Mac mini replaced my 2012 version which had no monitor problems. File Vault is off for me and doesn't make a difference. Any other ideas?

For what it is worth, I am using a LG 27UK850-W 27" 4K UHD monitor and connecting to the 2018 Mini with the HDMI/HDMI cable that came with the LG. When I check the (running) connection with System Information.app, I get:

 Graphics/Displays:

LG HDR 4K:

  Resolution: 3840 x 2160 (2160p 4K UHD - Ultra High Definition)

  UI Looks like: 1920 x 1080 @ 60 Hz

  Framebuffer Depth: 30-Bit Color (ARGB2101010)

  Main Display: Yes

  Mirror: Off

  Online: Yes

  Rotation: Supported

  Adapter Type: DVI or HDMI

  Automatically Adjust Brightness: No

  Adapter Firmware Version: 2.0a

Changing to a USB-C/USB-C cable gives me the same UI Looks Like resolution. Also,I don't repurpose any of the other monitor connections for charging or whatnot. So far, everything in my Sept 3, 2019 workaround seems to work--tap the shift key twice and immediate wake-y wake-y.

[Edited by Moderator]

I am a long term mini i7 user. I too had many problems with two monitors, FileVault, external drives.

i brought the mini in to Apple. They replaced the motherboard. Monitor problems went away... and I was happy for about 3 months.

but

i updated to 10.14.6 rev b. Ever since then, one or the other screen blinks out for a few seconds ‘ or one screen gets a blue tinge.

‘sometimes my tb3 external hard drives do not appear. The root cause? Bad things happen when I put big load on the mini, like]I gotta runninghuge Database’s where temp rises to 100 degrees c and the fan jumps to 4000 rpm. Soon after that, bad things start to happen.

i suspect that this is both a hardware and software issue. In other words, the mini i7 gets overloaded and drops communication with various items on the bus.

until Apple announces a replacement plan for the mini, better fan etc., or comes up with a reliable software solution, the solution is to switch to a iMac or new Pro, and retire the mini to perhaps an email server or some other lightweight duty

like a music box.

I suspect it was too much to ask to have a i7 six coreloaded with lots of monitors and external drives and running big computational loads. . The thermal issues are somehow

causing the mini to drop external load.

$1700 invested for the mini i7 512 gb. $10,000 wasted personal time fooling around with this box. Not a good strategy.

i just bought a dell i9 for $1400. Same or better specs than the mini. Hugely better thermal capacity in a desktop tower.

i will keep the mini as a 32 bit machine to I can run legacy Mac software. 10.15 64 but rules are simply dumb.

all my scanner drivers are e2 bit and no, Lexmark and hp are not likely to update their drivers on 4 year old $5000

off8ce mfc... they would rather you buy new $5000 machines.

apple is doing no one any favors by killing 32 bit. If windows 10 64 bit can run 32 bit programs, there is no reason

Catalina can’t... apple can leave in some legacy code do that all our scanners will continue to work

and, good news, with the dell, I don’t have to put up with parallels updates and license issues with multiple boxes.

It’s not a cable problem. I’ve tried several. Current one supports 4K 60hz. HDMI was working fine before Catalina. I’m booting from the internal drive.

Problem is there’s no display pre-boot coming from either HDMI or USB-C. Once it’s booted I can unplug USB-C and plug in HDMI and get a signal.

There’s a problem with the low-level driver that’s loaded before the OS. If you have FileVault enabled, it prompts for your password before the OS is loaded because your drive is encrypted.

even without FileVault, you cannot see any boot or recovery menu when you hold down Option.