Apple's Thunderbolt 2 Ethernet stopped working

[Andain]

Hi there !

I have a 2014 15" MacBook Pro that I am still happy about and enjoy as a main machine.

For the past 8 months, I've moved this laptop on Ethernet connection only and enjoyed the much faster speeds.
Now, for the past couple of weeks my connection simply stopped working.
At first, I thought my dongle died (it's an original Apple one) and just got a new one for cheap but the problem persisted on the new one as well.

Interestingly enough, the problem persists on both Thunderbolt ports. This is why I think/hope it must be a software issue rather than hardware. All of a sudden it just died, no intermitent connections.
If I go to System Preferences -> Network, this is what I get to the port that's being plugged. (see attached screenshot)

So it does somewhat recognise something being plugged.

Also, I am pretty confident it is not a problem from my router since I also use a switch to split my ethernet connection for a desktop PC and it works no problems, and I've also tried using just the main Ethernet cable to no success.


System Report says no connection for either of the ports.

I am running the latest Big Sur 11.2.3 and I also have bootcamp with the latest Windows 10 and same issue.

I am aware there are multiple topics throughout Google, but from what I've noticed, most of them imply that your connection is at least recognised and System Report shows 1 Thunderbolt slot being used/active, which is not the case for me.
Also, in those threads, most topics deal with Terminal-like commands that kind of play around with the Network Connections that I would try to avoid for now since I do not really want to mess things up and be forced to reinstall Big Sur.

Any ideas ?

edit: Apple Hardware Test found no issues.

 

[joevt]

What does it show in the Thunderbolt, PCI, and Ethernet tabs of System Information.app?
What about Catalina?

 

[Andain]

Hi !

Not sure if we are talking about the same thing.

When spotlight searching "system information.app" it opens the System Report from About this Mac I mentioned in the OP.

Under the Hardware column I can find "Ethernet Cards" and "PCI" which both say "This computer does not seem to have PCI/Ethernet card/devide installed".

The Thunderbolt you mentioned seems to fall under the Thunderbolt/USB4 tab which shows this :

Not sure what you mean with Catalina as I am running Big Sur.

Sorry for my lack of knowledge, haven't "troubleshooted" a Mac since Lion days I think.

 

[Andain]

Sorry for double posting, just want to make sure whoever visits this thread gets all the information as some may not check the edits from previous posts.

I am starting to think this may be Big Sur 11.2.3 related.
For example my headphone jack has an issue since Catalina days where the one side is heard at lower volume. Went to the Apple store a while back and the Genius booted an older version of macOS and the jack worked just fine.
It is also working fine in Windows 10.

So there software bugs, while rare, can happen.

Just went through Apple Support Chat and they tried diferent software tricks to pinpoint the issue

NVRAM/SMC both resets.
Created Test User account and Safe Boot (Apple's Safe Mode) to no success.


I will try to maybe re-install Big Sur but it is not an emergency now.

Also, anyone who has other tips or ideas please do not hesitate to share.

 

[joevt]

Not sure if we are talking about the same thing.
Under the Hardware column I can find "Ethernet Cards" and "PCI" which both say "This computer does not seem to have PCI/Ethernet card/devide installed".

The Thunderbolt you mentioned seems to fall under the Thunderbolt/USB4 tab which shows this :

If the Thunderbolt/USB4 tab is empty, then your Thunderbolt device is not connecting properly. Do you have any Thunderbolt devices that connect properly? If you have a Thunderbolt device with two ports, then you can connect the Ethernet adapter to the second port. If you have two Apple Thunderbolt 3 to Thunderbolt 2 Adapters, then you can connect a Thunderbolt 3 device to the MacBook Pro and the Thunderbolt Ethernet adapter to the Thunderbolt 3 device.

Not sure what you mean with Catalina as I am running Big Sur.

I was wondering if Catalina has the same problem or not. I guess it probably does if the problem is with Thunderbolt not working.