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r.d

macrumors regular
Original poster
Sep 2, 2007
111
145
Etobicoke, ON
I just updated my Mac mini 2018 to Big Sur, and the HDMI port no longer works.



I have a dual 4K monitor setup which has worked fine since I bought the computer.

Monitor 1: HDMI to HDMI

Monitor 2: USB-C/Thunderbolt to DisplayPort

Both monitors are the same brand/model.



Upon first boot into Big Sur after the update, one monitor wasn't working (the one with HDMI).



Troubleshooting I have done:

  • Confirmed the HDMI cable is fine (it works with another computer and the other monitor)
  • Unplugged all peripherals except for the HDMI monitor (result: no output)
  • HDMI monitor not showing up in Display settings


Troubleshooting done with Apple Support:

  • Reset NVRAM & PRAM
  • Reset SMC
  • Diagnostics Test (result: no issues found)


I will be doing a downgrade and Time Machine restore to Catalina in the next couple days to see if the Big Sur update broke the HDMI port, or if it’s a hardware issue.



>> Has anyone had a similar issue? Is there anything else I could try to get the HDMI port working before restoring?
 

jgosurf2020

macrumors newbie
Nov 17, 2020
1
1
I just updated my Mac mini 2018 to Big Sur, and the HDMI port no longer works.



I have a dual 4K monitor setup which has worked fine since I bought the computer.

Monitor 1: HDMI to HDMI

Monitor 2: USB-C/Thunderbolt to DisplayPort

Both monitors are the same brand/model.



Upon first boot into Big Sur after the update, one monitor wasn't working (the one with HDMI).



Troubleshooting I have done:

  • Confirmed the HDMI cable is fine (it works with another computer and the other monitor)
  • Unplugged all peripherals except for the HDMI monitor (result: no output)
  • HDMI monitor not showing up in Display settings


Troubleshooting done with Apple Support:

  • Reset NVRAM & PRAM
  • Reset SMC
  • Diagnostics Test (result: no issues found)


I will be doing a downgrade and Time Machine restore to Catalina in the next couple days to see if the Big Sur update broke the HDMI port, or if it’s a hardware issue.



>> Has anyone had a similar issue? Is there anything else I could try to get the HDMI port working before restoring?
I am having the same issue. I was able to get the monitor working yesterday for a brief time. Today, the HDMI monitor is not working.
 
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ilpap

macrumors member
Mar 27, 2010
77
19
Yes! finally, I was hoping someone will have the same problem (it couldn't be just me).

USB C: works fine in 2 different monitors (LG 5K & LG 4K)
HDMI: doesn't not work any more on 2 different monitors with different cables (LG 4K & Samsung 4K)

The monitor that doesn't work with HDMI works fine with USB-C (LG 4K)
The monitor detects the input once the cable goes in, but not the signal.
 
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r.d

macrumors regular
Original poster
Sep 2, 2007
111
145
Etobicoke, ON
Decided to downgrade to Catalina using a Time Machine backup. The restore completed successfully, but the computer wouldn't boot afterwards. Was getting a "Do Not Enter" symbol. So I booted into recovery mode and Activation Lock was on. So I entered my info and it said "authentication succeeded", but it still wouldn't boot. What a disaster. Ended up having to use Disk Utility to completely wipe the drive do a clean install of Catalina.

On the plus side, the HDMI port now works again, so clearly Big Sur caused it to stop working.

Wonder if this has something to do with it??
Apple Releases Revised Version of macOS 11.0.1 Big Sur

However, there's no way I'm upgrading any time soon. Hours and hours wasted.
 

IngerMan

macrumors 68000
Feb 21, 2011
1,878
772
Michigan
I upgraded Big Sur a few days ago. I Have a 2018 MM 38” Dell 4K. Vega 56 eGPU. It’s working fine. I was running HDMi MM to Display and eGPU T3 to MM then DP eGPU to Display. It worked but I changed MM T3 to USB-C Display removing MM hdmi and that works as well. No boot up issues with FV. If you want me to test something, ask away.
 
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ilpap

macrumors member
Mar 27, 2010
77
19
I see also that with a USBC-->HDMI adapter the monitor doesn't also work!
 

jcel

macrumors newbie
Nov 20, 2020
1
3
Same issue here. I have a Mac Mini 2018 connected to two identical LG 4k monitors, one over USB-C, the other over HDMI. This setup worked fine with Catalina. Since the update to Big Sur, whatever is attached to HDMI doesn't work anymore. NVRAM and PRAM reset didn't help.
 

thiagovalenti

macrumors newbie
Nov 26, 2020
1
1
a couple of days later, and it just stopped working again. (while on MacOS Beta 11.1)
Mine wasn't working on 11.0.1 (HDMI to a USB-C hub), updated to Beta 11.1 and nope didn't work either.
Any ideas if using a HDMI-USBc cable works? Seems like it's the HDMI interface that ruins it all, even the USB-A works on the hub I have to sync my iPhone.
 
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smoin1110

macrumors newbie
Nov 27, 2020
1
1
I signed up just to update you guys that I have the same problem,

Following were my tests:
Macbook USB C Port -> SATECHI USB C HUB -> HDMI to HDMI -> Samsung 4k Monitor = BLACK SCREEN (NO DISPLAY)
Macbook USB C Port -> CHOETECH USBC to HDMI 60Hz Cable -> Samsung 4k Monitor = BLACK SCREEN (NO DISPLAY)

Macbook Pro 2017 base version, MacOS Big Sur 11.0.1 (20B29)

FYI guys try with power cable connected! Though it didn't work for me, but Apple guide recommends connecting the Macbook to power source when connecting to external displays.

Please update me if you guys get it to work!
 
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sneffets

macrumors newbie
May 5, 2009
10
3
This is definitely a Big Sur issue...I have a 27" iMac 5K with an external 43" LG Monitor running 11.0.1, iMac is running at 5K and the LG supports 4K HDR via USB-C (thunderbolt). Just setup a new Mac Mini w/M1 running 11.0.1 and when I plugin two display ports, the second one does not work. Swap displays and they both work independently. I have a 43" 4K Dell USB-C to Display Port, and 27" 4K USB-C to display port. I was using a USB-C to Display port cable on the 43" and HDMI to the the 27", both 4K on my previous Mac Mini without any issues...I am going to upgrade the Intel based Mac Mini to Big Sur and see if I have the same issue. Daisy chaining the 27" to the 43" worked, but with Mirror only option and lower 2540 res on the 43", which was what is "supported" via the Dell specs. Kind of shocked, being a long time Mac user without a lot of issues over the last 14 years... = not good Apple, hard to imagine how they missed this issue, given the Beta testers were reporting this back in June/July from what I see on the forums. I do have a have a CalDigit TS3 Plus at home which will fix the issue until they correct it...but you guys aren't crazy...it's an issue :)
 
Last edited:
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Janeilfen

macrumors 6502
Feb 11, 2018
273
56
Does anyone know if this HDMI monitor issue only exists on multiple monitor systems? So if HDMI is your only connected monitor, does it work OK?
 

ilpap

macrumors member
Mar 27, 2010
77
19
Does anyone know if this HDMI monitor issue only exists on multiple monitor systems? So if HDMI is your only connected monitor, does it work OK?
It doesn't work for me. MacMini connected only on HDMI doesn't give signal.
 

sneffets

macrumors newbie
May 5, 2009
10
3
This is definitely a Big Sur issue...I have a 27" iMac 5K with an external 43" LG Monitor running 11.0.1, iMac is running at 5K and the LG supports 4K HDR via USB-C (thunderbolt). Just setup a new Mac Mini w/M1 running 11.0.1 and when I plugin two display ports, the second one does not work. Swap displays and they both work independently. I have a 43" 4K Dell USB-C to Display Port, and 27" 4K USB-C to display port. I was using a USB-C to Display port cable on the 43" and HDMI to the the 27", both 4K on my previous Mac Mini without any issues...I am going to upgrade the Intel based Mac Mini to Big Sur and see if I have the same issue. Daisy chaining the 27" to the 43" worked, but with Mirror only option and lower 2540 res on the 43", which was what is "supported" via the Dell specs. Kind of shocked, being a long time Mac user without a lot of issues over the last 14 years... = not good Apple, hard to imagine how they missed this issue, given the Beta testers were reporting this back in June/July from what I see on the forums. I do have a have a CalDigit TS3 Plus at home which will fix the issue until they correct it...but you guys aren't crazy...it's an issue :)
Update...using the CalDigit TS3+ would not work either...which "proves" it is an issue on the Mac Mini (new M1 and older) on Big Sir...with multiple displays...my iMac and MacBook Pro don't have "issues"...but the are each using an "internal display" and external...I can see if I can test my MacBook Pro with two external displays on Big Sur later today...
 
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ilpap

macrumors member
Mar 27, 2010
77
19
I updated to the new beta of 11.1 (20C5061b) and still the issue remains.
Both directly on the HDMI or via USB-C to HDMI adapter.
 

r.d

macrumors regular
Original poster
Sep 2, 2007
111
145
Etobicoke, ON
Thanks. I am staying with Catalina until some updates happen.

Me too.

I updated to the new beta of 11.1 (20C5061b) and still the issue remains.
Both directly on the HDMI or via USB-C to HDMI adapter.

Thanks for the update. I submitted a bug report to Apple when it first happened. I think we should all do the same to get their awareness.
 
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sneffets

macrumors newbie
May 5, 2009
10
3
Me too.



Thanks for the update. I submitted a bug report to Apple when it first happened. I think we should all do the same to get their awareness.
I did see someone on the Apple Forum from a few days ago that claimed to have spoken to Apple about the issue, and they were informed it is a known bug and should be fixed with an upcoming release, and as we know...their was no suggested work around.
 
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