Lost thunderbolt port with 10.15.4 Beta 6

hagjohn

macrumors 6502a
Original poster
Aug 27, 2006
743
655
Pennsylvania
I seem to have lost my thunderbolt port near the HDMI port on my Mini with beta 6. Anyone else have this issue?
 

mr_hyde

macrumors newbie
Nov 3, 2018
21
8
Italy
Yes, I had the same problem: I use that port for one monitor (it is connected to a USB-c HDMI adapter) so after the first reboot I lost the second monitor.
Now it is working again, not really sure which of the following actions solved the issue:
1) at the beginning I simply changed the USB-c port to verify if the problem was the monitor
2) I also tried to reset Pram (I still did not understand if that action still works in Macmini 2018
3) I unplugged the power cable for about 30 seconds

When I restarted the mini, after a while, the second monitor appeared again (obviously I re-connect ed it using the port nearest to the HDMI).

Bye,
Mr Hyde
 

richmond62

macrumors newbie
Mar 12, 2020
18
3
Indeed . . .

Suddenly my 3rd monitor stopped working, and all the ports on the USB-VGA converter went 'wonk' . . . thought it was the converter. Anyway, after a lot of pissing about it turns out that the port marked in green on the back of the Mac Mini seems to be 'dead', and I am able to get the 3 video signals out of the ports marked in orange (which the official Apple documentation says is not possible) . . .

ports.jpg

- - Post merged: - -

I hope that with the stable release of 10.15.4 that port will be restored to life.
 

frou

macrumors 6502a
Mar 14, 2009
728
787
Indeed . . .
Probably worth resetting the SMC as it sounds like @mr_hyde did:

Apple said:
Desktop computers with the T2 chip
  1. Shut down your Mac, then unplug the power cable.
  2. Wait 15 seconds, then plug the power cable back in.
  3. Wait 5 seconds, then press the power button to turn on your Mac.
---

Wiping NVRAM (aka PRAM) is a bit more drastic since there are often useful customizations in there.
 
Last edited:

richmond62

macrumors newbie
Mar 12, 2020
18
3
Well, anything is a port in a storm. :cool:

Wow! That worked: I love you. 💋
 
Last edited:

richmond62

macrumors newbie
Mar 12, 2020
18
3
AND, when I upgraded to 10.15.4 final last night I had to reset the SMC again . . .
 

richmond62

macrumors newbie
Mar 12, 2020
18
3
Of course "resetting the SMC" is just a fancy way of saying "yank the power cable out, count up to 20 and bung it back in again." :cool:

But . . . a long time ago I was told, "Never do that." Not, admittedly that is have ever stopped me on many occasions. 😇
 

weaztek

macrumors regular
Aug 28, 2009
143
57
Madison
Interestingly enough, that same USB-C port "broke" on my Mini when I upgraded to 10.14.6.

I immediately upgraded to Catalina and the port works again. So my hunch is it's updated firmware that breaks the port.
 

Erehy Dobon

macrumors 6502a
Feb 16, 2018
770
626
Of course "resetting the SMC" is just a fancy way of saying "yank the power cable out, count up to 20 and bung it back in again." :cool:

But . . . a long time ago I was told, "Never do that." Not, admittedly that is have ever stopped me on many occasions. 😇
LOL, whoever told you that is a moron.

They are shipped with the power cord removed. In fact, they sit for weeks at a time like this. And people do move around computers.

Be more discriminating about the advice you get. The worst ones start with "I read on the Internet..." without providing valid reliable sources.
 
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Fishrrman

macrumors P6
Feb 20, 2009
18,552
6,281
For 33 years now, I've kept my desktop computers connected to a power strip, which I switch OFF every night.
The computers continue to work just fine.
 

watakoola

macrumors regular
Aug 23, 2010
115
78
Australia
For 33 years now, I've kept my desktop computers connected to a power strip, which I switch OFF every night.
The computers continue to work just fine.
EEEEK! When I first read that I thought you shut the computer down by turning the power strip off each night!o_O
 

bernie-uk

macrumors newbie
Jan 10, 2012
9
1
I had the same issue installing Security Update 2020-002 on Mojave 10.14.6, with one of my two displays not working.

I have previously had the motherboard fail on this mac mini, so assumed it might be an overheating issue - luckily pulling the power out for 30 seconds to reset the SMC resolved it. You would think Apple might mention the issue !

The first Thunderbolt port closes to the HDMI port has a special role for communicating with the T2 chip / BridgeOS.
I presume the security update probably includes some firmware update for T2.

When my motherboard previously failed and would not boot, the Apple store still could recovery my data from the SSD using a program only available to them unfortunately, which connects two macs together using that Thunderbolt port. You can also put the machine in DFU mode using the Apple Configurator tool and that port, so it has a special function.

This support article is also useful, which shows how the four ports are organised in two buses
https://support.apple.com/en-us/HT209224 Connect multiple displays to your Mac mini (2018)

As an aside, macOS never recognised the full resolution of my Acer monitor (always defaulting the 4K monitor to 1920x1080), so I had set the scaled resolution set using the ALT key. After waking the mac mini, the CPU usage would always jump as it re-arrange the sizes for all the windows.
I've noticed that if I use the Scaled "More Space" to define the resolution of the monitor, it's better since it does not resize all the windows each time I unlock the machine.
 
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