After updating to Catalina, Mac Mini 2018 does not send any HDMI signal.
It was working fine today, until the Catalina update.
Can not enter safe mode nor recovery mode.
Tried resetting NVRAM, no change.
Just in case, I tried another cable and I also tried connecting it to AVR, but still no signal.
Mini is connected to 4K TV, I don’t have any other option (except USB-C to HDMI adapter which I don’t have).
Mac mini 2018 or later
Samsung Monitor will not be recognized at system start on Mac Mini 2018 after Upgrade to OS Catalina 10.15.2.
No problems with OS 10.14 before.
My personal (hopefully temporary) bypass:
After having pressed the power on button on the Mac mini, I unplug the HDMI cable and plug it in again at the Mac mini. Afterwards, I switch the Monitor power on and everything is working fine.
It seems, that the Mac mini doesn't receive an interrupt from the monitor, if the monitor is already powered on at systemstart.
Samsung Monitor will not be recognized at system start on Mac Mini 2018 after Upgrade to OS Catalina 10.15.2.
No problems with OS 10.14 before.
My personal (hopefully temporary) bypass:
After having pressed the power on button on the Mac mini, I unplug the HDMI cable and plug it in again at the Mac mini. Afterwards, I switch the Monitor power on and everything is working fine.
It seems, that the Mac mini doesn't receive an interrupt from the monitor, if the monitor is already powered on at systemstart.
The problem was fixed for me with the newest update 10.15.3.
HDMI to HDMI now works just fine with my Samsung 4K monitor.
With USB-C to HDMI there are still some problems with a black screen while booting.
Anyway: I'm glad that it works now. I paid around $3,000 for my Mac Mini and had 5 months were I couldn't use it correctly. I am very disappointed that something like this could happen with an Apple product.
In the end, I bought an HDMI/USB-C adapter with 4K support
This thread prompted me to try a pair of USB-C to DVI cables instead of USB-C to HDMI and they worked fine. Of course that doesn't help if your external monitors don't support DVI. Whatever the case it is still surely a software bug.
I am pretty sure this is an issue with HDMI and Catalina. When using my two external monitors with USB-C to HDMI leads it takes ages for them to be recognised (30 mins or more). I switched them for USB-C to DVI cables and the monitors are recognised instantly.
No! Even the new adapter, model A2119, does NOT guarantee 3840x2160 at 60Hz - https://support.apple.com/en-ca/HT207806
As a matter of fact the Mac Mini isn't even mentioned in the material from Apple:
Model A2119 is the newest model of this adapter. It supports HDMI 2.0 at these resolutions and refresh rates when used with macOS Mojave 10.14.6 or later or iOS 12.4 or later. It also supports HDR video in HDR10 and Dolby Vision formats when connected to a compatible playback device and display, TV, or projector.
Recently updated to macOS 10.15.1, display issue via hdmi persists
Anyone else still having issues after updating to macOS 10.15.1?
The issue seems to be resolved for me. I moved my Mac mini to a different room over the weekend, and when I hooked up my monitor I left the HDMI to USB-C adapter workaround aside, plugging the monitor directly into the HDMI port. It’s been a few days and I haven’t experienced any of the same issues I used to. I’m running Catalina 10.15.3.
cwanke72 mentioning lower res displays led me to workaround.
I dismissed it at first because I do not have any other displays except Sony 4K TV.
Then I remember Sony has two "30Hz non HDR" HDMI ports.
I connected Mac Mini to one of those, had to shutdown Mini (it was powered when I changed connection) and after I turned it on - signal was finally reaching TV.
Now I need to figure out how to make it work on 60Hz HDR port.
It may be that the LG's "Color" feature is directly related to HDR ... and this may be the common clue here with the mini's HDMI port. My Dell does allow me to switch HDR on or off, so I had to resort to using a USB-C-to-HDMI adapter to get my mini to display.
Interestingly the Apple Technical Specs for the 2018 mini do not include any information about HDR support, but does inform us that this mini does have a HDMI 2.0 port ... which according to the standards, supports HDR.
FWIW. I think we all share the same frustration with using the HDMI port on the 2018 Mac mini with 4K monitors. However, whether it's macOS, Windows, Linux, you name it, any first major release to the public is still a "beta" ... and it's the conundrum of having the very latest vs. bug free. It would be impractical, if not impossible, to test every possible combination of hardware to verify perfect operation, that's why we see X.1, X.2, X.3, etc. releases not long after. Can Apple do better ... sure! But, two ways to assist Apple, is to participate in the public or developer betas and providing Apple with direct feedback when something isn't working. This forum is intended to be a means for Apple-product users to support each other with potential solutions. In this case, this issue appears to be around using the HDMI interface on the mini with 4K monitors, especially with HDR support ... and so far, either disabling HDR and continue to use the HDMI or switch to using the USB-C-to-HDMI adapter are the only potential workarounds. Maybe with Catalina 15.1, Apple will hear us and offer a fix.
One suggestion to everyone here, is if you want to try any new OS release, major or minor, create a bootable clone of your Mac's drive to an external one. Upgrade that cloned drive to that new release and try it out for a few days or weeks making sure that all of your critical apps and hardware work as you expect it to ... and, if you are satisfied that it does, then upgrade your system drive. This way you have the opportunity to "test drive" it before "buying" it.
Just have the bulletin from someone else, text below.
Apple Technical Service Bulletin
This document provides additional instructions for operating the Mac Mini (Late 2018)
macOS Catalina 10.15
Mac Mini (Late 2018) users should refrain from upgrading to macOS Catalina 10.15.
https://www.apple.com/macos/catalina/
Information about products not manufactured by Apple, or independent websites not
controlled or tested by Apple, is provided without recommendation or endorsement. Apple
assumes no responsibility with regard to the selection, performance, or use of third-party
websites or products. Apple makes no representations regarding third-party website
accuracy or reliability. Risks are inherent in the use of the Internet. Contact the vendor for
additional information. Other company and product names may be trademarks of their
respective owners.
Published Date: October 12, 2019
Only 30 Hz possible (https://support.apple.com/en-us/HT207806)
Intel UHD Graphics 630:
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:
LG Ultra HD:
Resolution: 3840x2160 (2160p/4K UHD 1 - Ultra High Definition)
UI Looks like: 1920 x 1080 @ 30 Hz
Framebuffer Depth: 30-Bit Colour (ARGB2101010)
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Adapter Type: Apple USB-C Digital AV Adapter
Automatically Adjust Brightness: No
Adapter Firmware Version: 2,35
Don't know if it has been mentioned here before but there is a special page to report any bug here : https://www.apple.com/feedback
I contacted the support again and they told me that the apple dev team is looking at those feedbacks.
I guess it is more effective to contact them directly rather than discussing between us.
I hope this issue will be fix quickly, it's very crippling.
OMFG...... This got fixed with 10.15.1, then yesterday I stupidly updated to 10.15.2 and NO MORE HDMI!!
WTF Apple? Seriously, this is freaking ridiculous!
No HDMI signal after update
