Catalina causing issues with HDMI

shinji

macrumors 65816
Mar 18, 2007
1,309
1,501
I'm not having this issue with a P2415Q connected HDMI->HDMI. Also have an Apple Cinema Display connected via DVI->USB-C.

But my displays never sleep no matter what Energy Saver settings I use.
Ok, after doing today's supplemental update, it's still functioning, but I no longer have 4k@60hz. I had already changed the setting in the Dell menu to enable it, and 4k@60hz was working fine on Mojave and even Catalina before today's update.

I'm receiving an DP->USB-C adapter tomorrow to try to see if that fixes it.
 

Killerbob

macrumors 65816
Jan 25, 2008
1,014
80
One MAJOR problem with using a USB-C -> HDMI adapter is that the USB-C connections do NOT carry Dolby Digital. Hence, you can use the adapter for video, MP3s, but not multichannel audio... So not a solution in my eyes.
 

shinji

macrumors 65816
Mar 18, 2007
1,309
1,501
So I got the Belkin USB-C->HDMI adapter from Apple, and I'm still only getting 30hz, despite that exact adapter working for someone else in this thread https://discussions.apple.com/thread/250715830?page=2

I tried disabling and re-enabling support for HDMI 2.0 in the Dell menu, I tried rebooting, tried a cold start with only the P2415Q connected rather my Apple Cinema Display, etc. There was also a weird issue at one point where the colors suddenly all went very green/pink and then went back to normal.

Now I'm waiting for UPS to deliver the USB-C->Displayport cable I ordered so I can try that.

Edit: 4k@60hz is now working with USB-C->Displayport. Cheap Startech cable from Amazon.
 
Last edited:

Alwis

macrumors newbie
Jan 12, 2017
24
6
I wish I had found this thread earlier...

I have a 2018 Mini as a headless Server (with a Newetech HDMI headless adapter) in my server cabinet. After first upgrading to Catalina, the Mini did not start. First I tried a cold reset and a NVRAM & PRAM reset. As this did not work I moved it to the monitor in my office.

The monitor showed an error regarding the screen resolution, but I managed ti get the Mini booting by disconnecting the monitor while powering it up. Pluggin it back in after a few seconds, the Update continued and finished successfull.

After that I tried some more reboots, with monitor and headless adapter connected and everything was fine. So I moved the Mac back in my cabinet.

Today I installed the new update, but I had the same issue. I could resolve it by disconnecting the HDMI adapter and power cycling the Mini.

All in all that cost me several hours, reminded me of my Windows times, ages ago, when I spend more time working on the OS than doing the work I wanted to do with the computer.
 

chrfr

macrumors G3
Jul 11, 2009
8,379
2,632
Can anyone corroborate this document? I could type something up and claim it's from Apple just as easily as this document claims to be.
 

tu2thepoo

macrumors member
Nov 14, 2017
75
58
Wow, I really wish I'd checked the forum before upgrading, I ran headlong into this issue.

Working state (before upgrade):
  • TCL S403 (4k, 43" TV) connected via HDMI port
  • Latest version of Mojave
  • Windows 10 working via eGPU (Geforce 1080), plugged into second HDMI port on TV
Post-upgrade, I got stuck in multiple boot loops, blank screens, and failed installations. The few times I got it to boot to login, there was color corruption and screen blanking (pointing towards some kind of HDMI handshake issue). What did NOT help:
  • Reverting to Mojave via USB installer
  • Wiping internal SSD (I have backups!) and installing clean
  • Wiping USB-C SSD and installing clean
  • Internet recovery
  • Removing aftermarket RAM and going back to stock RAM
  • Trying a second, 1080p TV (it successfully booted sometimes but inconsistently)
I took my Mini to the Genius Bar, and as soon as he plugged in an old 20" 1080p monitor (to the HDMI port) it booted perfectly fine. When I took it home, the boot loop came back.

Here's the super weird part changing my TCL TV from "HDMI 2.0 only" to "HDMI 1.4 only" then back seems to have solved... everything. I'm going to reboot to confirm. I also have a USB-C to HDMI 4kp60 adapter coming in tomorrow to test.

[edit]
lol it’s broken again after a restart
 
Last edited:

weaztek

macrumors regular
Aug 28, 2009
127
45
Many of us had similar issues during the upgrade and post upgrade process.

What I found is working is: a USB-C to DisplayPort cable (mine is Warrky brand). And reseting the SMC and NVRAM on the Mini. That, along with restarting a few times helped me.
 
  • Like
Reactions: tu2thepoo

phoenix-mac-user

macrumors member
Sep 21, 2016
35
19
I have having this issue as well. I have been running Catalina since it released and it just started happening today. My 34" ultrawide running from HDMI t HDMI doesn't work. Guess I am going to have to buy a USB-C cable which is annoying.
 

killawat

macrumors 65816
Sep 11, 2014
1,446
2,191
I have Mac mini 2018 connected to rx 580 sonnet egpu.

Upon boot up I get low res boot screen for FileVault which is an improvement for no video but the color profile is always messed up. Screen looks normal or purple/green.

Next after boot I can't get video output through eGPU as expected. I have to plug in a display to one of the USB-C ports then hot plug my eGPU to get video output.

Knock on wood sleep wake works fine but when I need to restart it's a major headache.
 

phoenix-mac-user

macrumors member
Sep 21, 2016
35
19
Weird. Mac mini 2018 with Vega 64 egpu, LG 4K TV. Haven’t had a problem with either intel 630 or the Vega, both over hdmi.
I didn't have a problem until almost a week after installing Catalina. Just started happening yesterday.

So I called Apple Support last night and they gave me a "solution". They told me to shut down my computer and unplug for 15 seconds and then plug it back in and wait for 5 seconds and turn it back on, which I didn't know was a thing. And it worked!

Except I have to do this EVERY TIME I wake my computer up from sleep mode. I have done this "fix" 4 times now.

So I will be calling them back tonight.

Maybe the most annoying thing is with this thread and the bulletin, they obviously know what is going on and they have a problem, but instead tech support for Apple Care plays stupid about it and I spend 20 minutes answering stupid questions. I finally mentioned "I read that there is a problem with Catalina using HDMI", which then quickly brought me to the "fix", which is not going to work for more than a day without driving me insane.
 

cwanja

macrumors 6502a
Jun 23, 2010
630
282
Texas
Can confirm I have the same issues on my Mac mini (late 2018) connected HDMI -> HDMI LG Ultra HD monitor. It seems to have issues waking up from a "deep sleep" (overnight, a few days, etc.). But if it is just a few hours, the display kicks on just fine. I can VNC into the Mac mini to make sure it has no issues and routinely that has worked - until this morning. When I VNC, all I saw was black and grey squares like a checkerboard table. Hard reboot got things started.

Not the greatest update cycle for Apple ever.
 

weaztek

macrumors regular
Aug 28, 2009
127
45
So I called Apple Support last night and they gave me a "solution". They told me to shut down my computer and unplug for 15 seconds and then plug it back in and wait for 5 seconds and turn it back on, which I didn't know was a thing. And it worked!
Yep, that resets the SMC. I've had to do it a few times, but luckily my Mac is now working with my LG monitor over a USB-C to DisplayPort cable.

For what it's worth here are the Energy Saver settings I'm using successfully (because I think some of the issues are related to sleep on the Mini).
 

Attachments

Duncan68

macrumors regular
Sep 22, 2018
232
176
So why does it seem like the mini is Apple's redheaded step-child, even though they released the newest one only last year?

Very little care or thought was put into how Catalina would affect the mini.
 

tu2thepoo

macrumors member
Nov 14, 2017
75
58
Wow, I really wish I'd checked the forum before upgrading, I ran headlong into this issue.

Working state (before upgrade):
  • TCL S403 (4k, 43" TV) connected via HDMI port
  • Latest version of Mojave
  • Windows 10 working via eGPU (Geforce 1080), plugged into second HDMI port on TV
Post-upgrade, I got stuck in multiple boot loops, blank screens, and failed installations. The few times I got it to boot to login, there was color corruption and screen blanking (pointing towards some kind of HDMI handshake issue). What did NOT help:
  • Reverting to Mojave via USB installer
  • Wiping internal SSD (I have backups!) and installing clean
  • Wiping USB-C SSD and installing clean
  • Internet recovery
  • Removing aftermarket RAM and going back to stock RAM
  • Trying a second, 1080p TV (it successfully booted sometimes but inconsistently)
I took my Mini to the Genius Bar, and as soon as he plugged in an old 20" 1080p monitor (to the HDMI port) it booted perfectly fine. When I took it home, the boot loop came back.

Here's the super weird part changing my TCL TV from "HDMI 2.0 only" to "HDMI 1.4 only" then back seems to have solved... everything. I'm going to reboot to confirm. I also have a USB-C to HDMI 4kp60 adapter coming in tomorrow to test.

[edit]
lol it’s broken again after a restart
Many of us had similar issues during the upgrade and post upgrade process.

What I found is working is: a USB-C to DisplayPort cable (mine is Warrky brand). And reseting the SMC and NVRAM on the Mini. That, along with restarting a few times helped me.
just to update - USB-C to HDMI works fine I bought this lention branded one, currently running 3840x2160 @ 60hz via HDMI to my TV. I set the TV back to HDMI "auto" mode (auto switch from 1.4 to 2.0).

Before it arrived, I had somewhat repeatable success by booting with a separate TV (1080p, HDMI), then switching to my 4k TV after the Mac mini booted. I couldn't boot with the 4k TV (even when forcing HDMI 1.4), but I could switch displays after the fact. I only tinker with the stuff, but it seems like an HDMI handshake issue or even a YCbCr/RGB issue.
 

honestone33

macrumors 6502
I have a late 2012 Mac Mini, and I am using a 2004 Sony 19" Monitor with it (still rock solid after all these years, as I purchased it back in 2004!). I have, via the Mini, installed Catalina on an external SSD for brief testing purposes, and had no issues. I actually plan on replacing my current Mini with a 2018 model, as this 2012 one will, most likely, not be compatible with the next version of the Mac OS.

I suspect I'lll be fine once I install Catalina permanently on my Mini (and on my mid 2017 Mac Book Air). Still have a ways to go with that, as I suspect TechTool Pro will not have a version compatible with Catalina until November or December, at the earliest. That's fine with me, as Mojave is working just fine.
 
  • Like
Reactions: OldGreyGuy

Spectrum

macrumors 65816
Mar 23, 2005
1,402
758
Never quite sure
Can anyone corroborate this document? I could type something up and claim it's from Apple just as easily as this document claims to be.
Well, I've had the post I wrote questioning the authenticity of the "service document" deleted. So I can presume that it was a fake bulletin.
I'm wondering why the admins didn't add a post to that effect here though...
 

kaibob

macrumors regular
Jun 21, 2010
232
62
Prescott, Arizona
The forum member who posted the service document posted a second service document essentially announcing that it was all a hoax. I assume (or at least hope) that we will see no more of that guy.