Mac mini 2018: no start up (terminates signal to monitor)

Hi,

1- Try Mac Mini with other display (inc. 4K TV)

2- Try LG 27UK850-W with other computers

3- Make sure that you are using right cable. More info> https://www.intel.com/content/www/us/en/support/articles/000023945/graphics-drivers.html

4- Check if the display matches the following specs:

Processor Graphics

• Processor Graphics ‡
• Intel® UHD Graphics 630
• Graphics Base Frequency
• 350 MHz
• Graphics Max Dynamic Frequency
• 1.20 GHz
• Graphics Video Max Memory
• 64 GB
• 4K Support
• Yes, at 60Hz
• Max Resolution (HDMI 1.4)‡
• 4096x2304@30Hz
• Max Resolution (DP)‡
• 4096x2304@60Hz
• Max Resolution (eDP - Integrated Flat Panel)‡
• 4096x2304@60Hz
• DirectX* Support
• 12
• OpenGL* Support
• 4.5
• Intel® Quick Sync Video
• Yes
• Intel® InTru™ 3D Technology
• Yes
• Intel® Clear Video HD Technology
• Yes
• Intel® Clear Video Technology
• Yes
• # of Displays Supported ‡
• 3
• Device ID
• 0x3E9B

5- More info about the processors the Mac Mini use:

https://ark.intel.com/products/126685/Intel-Core-i5-8600K-Processor-9M-Cache-up-to-4-30-GHz-

https://ark.intel.com/products/134905/Intel-Core-i7-8700B-Processor-12M-Cache-up-to-4-60-GHz-

Same here, Mac Mini 2018 boots up without display with the following setup:

• Display LG 27UK850
• Display connected via TB3/ USB-C out from Mac to USB-C in of Display
• macOS 10.14.2

The Mac Mini is the only machine that is connected via USB-C to the display. And it is the only machine that has issues with it.

The display works flawless with:

• MacBook (Mid 2012) Running macOS 10.14.2 connected via miniDP to DisplayPort
• PC running Windows 10 connected via DisplayPort to HDMI
• Notebook running Windows 10 connected via HDMI to HDMI

For Test I connected the Mac Mini via HDMI to HDMI with the LG display, now. Several reboots did not show any issues so far...

From my observations, your SMC resets are not necessary. The display has no signal until you are logged in. Have you tried blindly entering your password when it's dark? For me, the screen then always turned on. The reason: drivers are not available until the disk is decrypted, which happens after entering the password. Hence your options:

1. Buy an expensive apple monitor or similar with an actual thunderbolt 3 port
2. Blindly guess when you have reached the login screen and enter the password
3. Turn off filevault

Now choose the lesser evil. @mrg4guy

I have a similar issue. I can only get it to start and make it to the log-in, if I have a USB C only monitor. If I use a USB C to DP monitor, it wont't make it. Same with my TB3 eGPU. Once I get it started, I can unplug the USB C (ASUS MB169C+) and it will continue to work. The moment I shut it down or restart, it won't boot to the monitor. The large DP monitor is set to the be the default, and once I log-in on the smaller one, the main Mac OS screen bounces back to the main monitor.

Hi,

I have a similar issue. I bought LG 27UK850-W 27" for Mac Mini 3.0GHz 6-Core Processor with Turbo Boost up to 4.1GHz 256GB SSD. When I first start up the computer the monitor did not switch on. Eventually, I got it working with trying USB-C and HDMI connections alternatively.

However, the computer was struggling to keep up with a simple task. Then I start having display waking up problem up accompanied by some audio card issue.

To find the source of the problem, I tried to connect the mini over my Sony TV (1080dpi) with HDMI input. It worked like a magic. I had no issue with anything. I returned the monitor and don't know exactly what to do now. I really don't understand whether this is a mechanical or software problem.

I forgot to mention that Mac Mini produce a high pitched sound from the computer itself while Ableton Live is running (External Headphones out is selected). With Logic Pro X everything is looking normal.

Another issue that I have now is that there is a buzzing sound is coming from the External Headphones Out. This is only happens when I connect the USB 3 Hub (powered) to one of the USB port of the Mac Mini.

That sounds like an interference problem with your USB hub/its power supply. What is connected to the hub? Maybe one of those devices are causing the problem.

Another issue that I have now is that there is a buzzing sound is coming from the External Headphones Out. This is only happens when I connect the USB 3 Hub (powered) to one of the USB port of the Mac Mini.

Just got off the phone with the Apple Support Engineer I've been working with for a few weeks on reproducing this issue. He informed me that the engineers there are aware of this issue and that there will more likely than not be a software update to address it.

I also spent a few hours on the phone with Apple tech support, but they were not able to help. I've tried

HDMI -> DVI

Thunderbolt 3 -> DVI

I will try TB3 -> DisplayPort tomorrow on a different monitor and see if I can get any display.

Is this just a limited problem to a few Mac Minis? If so, why? Or do all 2018 Mac Minis running 10.14.2 have no display?

Also I'd like to try installing 10.14.0 to get the display back. Does anyone know how to find 10.14.0?

You asked "Also I'd like to try installing 10.14.0 to get the display back. Does anyone know how to find 10.14.0?"

The only way is if you made a copy/clone of your Mini when it had 10.14.0. However, if you contact Apple they may be able to provide it.

The TB3 -> DisplayPort cable worked finally! I guess the problem is limited to DVI or perhaps HDMI.

To summarize, with Mojave 10.14.2 (and probably 10.14.1 too),

the Mac mini 2018 will boot up and function normally but will have:

NO DISPLAY after boot with TB3 -> DVI

NO DISPLAY after boot with HDMI -> DVI

Normal display with TB3 -> DisplayPort

Other cables / configurations to be tested.

I have the exact same monitor (LG 27UK850-W) and 2018 Mac Mini i7 custom build with the same problem. I spent about 3 hours in total over several phone calls with apple technical support who recommended I bring everything to an Apple Store for proper setup. The technician at the Apple Store did a bunch of troubleshooting (running a diagnostic, resetting PRAM, resetting SMC) and we were not able to get my monitor working correctly over HDMI or USB-C. This store had a different 4k LG monitor that worked perfectly when connected with USB-C. In conclusion the store said there was a problem with my monitor and I should be contacting LG. My Mac Mini shipped with 10.14.1 so I've had this problem since day 1. I hope Apple can resolve this with a software/firmware update quickly.

NOTE: For me, when the monitor is connected via HDMI, an SMC reset will bring the monitor back to life until I shutdown the mac. (An SMC reset when connected via USB-C doesn't seem to fix anything) Once I shutdown the mac I need another SMC reset to bring the monitor back. I have my Mac set to never put the computer to sleep, only the display to sleep and waking the display with this configuration is usually not an issue.

Interesting that the SMC reset works for you. I tried it but no luck. I even tried booting from a 10.14.0 USB drive, no luck.

In all cases I'm able to see the Apple logo and progress bar, or the boot options screen by holding alt, but after the logo, there is no video output. What's funny is out-of-the-box, it worked fine. But once I hit sleep, I never got a display again.

I finally got it to work! The SMC reset worked for the USB-C -> DVI. However, it does not work for my HDMI -> DVI. This is with 10.14.2. I tried various HDMI -> DVI cables, including one rated as "dual link" but no luck. I have not however tried an Apple branded HDMI to DVI adapter which is what Apple support recommended I try.

My monitor is a DoubleSight DS-263N 1920 x 1200 IPS screen with VGA & DVI inputs. http://www.doublesight.com/files/ds-263n-manual-final.pdf