2018 Mac Mini - monitor problems

I tried USB-C to HDMI and I finally have a display when I power on, but now I have no display on reboot. It’s the reverse problem from what I had before.

With HDMI to HDMI and USB-C to DisplayPort, I have display on reboot, but no display when I power on. I have to blind type my password. I finally get a signal 3/4 of the way through the boot.

Hi all, I got the same problem for the past week since I upgraded my mac mini 2018 i3 128g SSD to the the most recent Mohave, 10.14.16. I use Kenowa portable monitor 13 inches, which connects with my mac mini through type C cable. I try also another monitor with VGA port, using type c - to - VGA. Before this update, both monitor worked well. Now It sometimes work, sometimes just blank screen. Every time like so, I have to hold-press the power button on mac mini to shutdown then start again an it recognizes the monitor. I searched on google I found out a lot of people have this problem. Then some said the reason is that mac mini just works well with a good monitor through type C. Any idea about this problem, should I upgrade to Catalina, or to buy a new monitor (if so, I plan to buy Dell P2914HC with type C connector). Thanks for help!

I'm still having problems on my 2018 mac mini. When there is any video activated in the browser, the screen flickers. Previously had apple hdmi converter hooked to monitor, until apple discontinued support for it. Now using USB-C converter, but flickering issue remains.

That's exactly how the replacement Mac Mini work for me - but on my first one with the same cable from LG, it just wouldn't switch on at all.

When it does take a few seconds I can't help but think its stopped working again!

I got the same problem that mac Mini does not wake up the monitor and told that in a post here. Now I bought a new monitor which is new released in 2019, Dell P2419hc with type C port, and the same problem still happens. Sometimes it works sometimes not. Very disappointed with apple now. I did not have this feeling under Steve Jobs, but Tim Cook is doing very bad. If not because of Mac OS, I would not buy a mac!! I'm using 10.14.6 and do not want upgrade to Catalina because I worry that the screen will complete not wake up anymore (like some reported here).

Sorry to hear that.

The above fix still appears to be working 24 hr on after many power-ups, wake-ups and re-boots.

Just in case it helps:

One thing that I have noticed since applying the fix is a change in the wake-up/re-start display.

Before applying the fix the display would start in very high resolution. The password box would appear very small in the centre of the login screen. After login the screen would adjust from max resolution to a lower resolution.

After applying the fix, I no longer see the max resolution login page. The login page is now displayed at a lower resolution.

This is hidden away in the MacOS Catalina 10.15 User Guide under the Use Multiple Displays topic at https://support.apple.com/guide/mac-help/use-multiple-displays-mchl7c7ebe08/mac

Note that it states that you may have to press the Option key to make the Detect Displays button appear. Interesting that this wasn’t mentioned in so many phone calls with Apple support techs. I guess it’s just as thoroughly hidden away in their knowledge base.

This has not helped me. Apple has been seriously downgraded in my book after this experience. I will never purchase a Mac Mini again and perhaps that is by their design. Nothing but repeated contacts to support regarding display issues. Their response now, it is out of warranty. IT WAS NEVER FIXED IN THE FIRST PLACE. Warranty should be extended in cases like this. This is definitely worth a class action in my opinion.

In year 2020 not working HDMI port is completely unacceptable.. Mac mini 2018 is 1+ year and I think this will be never fixed or may be is hardware issue... I plug and unplug my monitor every day once or twice or more... THANK YOU APPLE for this amazing experience...

Well, I was so happy that applying 'Detect Displays' fixed the 'Mac Mini not detecting displays problem'. That all changed this morning. After applying the latest OS upgrade the old not detecting monitor problem is back with vengeance.

Give me strength....

I updated mine and it worked last night but when I turned on my computer today, it doesn't read my 3rd monitor. I have LG 24in 4k monitors and its only reading two. anyone find a fix for this? I've tried turning it off and on and unplugging and plugging and nothing.

Sorry for the delay - here's the complete report:

Chipset Model: Intel UHD Graphics 630

  Type: GPU

  Bus: Built-In

  VRAM (Dynamic, Max): 1536 MB

  Vendor: Intel

  Device ID: 0x3e9b

  Revision ID: 0x0000

  Metal: Supported, feature set macOS GPUFamily2 v1

  Displays:

HP 27es:

  Resolution: 1920 x 1080 (1080p FHD - Full High Definition)

  UI Looks like: 1920 x 1080 @ 60 Hz

  Framebuffer Depth: 30-Bit Color (ARGB2101010)

  Display Serial Number: 3CM74000JM   

  Mirror: Off

  Online: Yes

  Rotation: Supported

  Automatically Adjust Brightness: No

  Connection Type: DVI or HDMI

  Adapter Firmware Version: d.1d

HP 27es:

  Resolution: 1920 x 1080 (1080p FHD - Full High Definition)

  UI Looks like: 1920 x 1080 @ 60 Hz

  Framebuffer Depth: 30-Bit Color (ARGB2101010)

  Display Serial Number: 3CM74000M1   

  Main Display: Yes

  Mirror: Off

  Online: Yes

  Rotation: Supported

  Adapter Type: DVI or HDMI

  Automatically Adjust Brightness: No

  Adapter Firmware Version: 2.16

Nope. Still have the same issue with my Mac Mini. If I connect my 4K TV directly to the Mac Mini HDMI port, the system preferences -> displays shows the correct display name on the window ( My Seiki 39" inch is identified as SE39UY04 ) but the Resolution default for the display is 1920 x 1080 and under the list of options in the "Scaled" list, I can only scale it to a lower resolution. HOWEVER, if I connect the HDMI cable to a thunderbolt to HDMI adapter, I get extra options under the "Scaled" list, one of which is 3840 x 2160 ( a 4k display ).

jose68 can you verify if you're USB-C to HDMI supports and is running at 60hz or not? I suspect the issue is with the built-in HDMI port and 60hz. Seems to be ok with 30hz but that's way too low for my eyes.

Can you explain about the adapter? Are you using an external Bluetooth now to fix it? How do you make the computer default to the external Bluetooth radio? (I have one sitting around somewhere).

The Mac Mini 8 is indeed a mess, between video and Bluetooth interference (and the weird On switch on the back, I guess you're not supposed to use that... wish they had a status light on the back too, it's easier to have the active end facing me...)