Thunderbolt Ethernet not working after Yosemite upgrade

Some info for anyone still having this issue and how i resolved my issue..

My issue, i was having issue with my Thunderbolt so i deleted it from the network preferences pane. It would not come back when i reinserted it.
I played with the network locations with no results.

The Macbook pro i use could see that the hardware was there (described in the steps below).

I manually tried adding the adapter back using Network preferences, and i had 3 of them to choose, but adding any one of them did not help. Most of the time the adapter would either never show up, or show up but never connect.

I needed a way to fix this adapter "without erasing" all my network configurations, vpn connections etc.

Here is what i did. Its alot of reading but thats only because i wanted to provide someone less familiar with Mac configuration, some more exacting steps.

First, let me point out that making sure your Thunderbolt shows up as a device in your system report is important. To do that:

1. Attach your thunderbolt Ethernet adapter....Click your apple menu, select about this mac, click system report
2. Towards the bottom of the hardware list click on Thunderbolt. And on the right you should see "Thunderbolt Bus"
3. Indented under it, while the adapter is plugged in, you should see "Thunderbolt to Gigabit Ethernet adapter"

If you see it, your half way there to resolution. If you don't see it, you may have a thunderbolt bus issue or your adapter could be bad.
This post is for those that see it, but cannot get the device to show up (auto detect) in the Network Preferences part of System Preferences.

What i found is that the easiest way to make sure your system detects it as a new device is to clear out the definition for the old one and let it re-detect. I didn't have an success with using the GUI tools to do this, i edited a plist file manually. Here are my steps:

1. unplug the Thunderbolt Ethernet adapter and reboot.

2. open finder. From the menu select GO | Go to Folder. Enter /Library/Preferences/SystemConfiguration

3. You will find a file there called NetworkInterfaces.plist. Open it with TextEdit

4. This file is organized using XML headers meaning <dict> marks the beginning of a section, and </dict> marks the end of that section and then repeats.

5. Inside each section you want to search for the word "Thunderbolt." I am attaching a sample image with 1 section by itself for ease of viewing.

6. In my situation i had 3 of them.. Thunderbolt, Thunderbolt1, and Thunderbolt2. These sections define the info on the interface.

7. Remove the entire section including the starting <dict> and the ending </dict> for that section. Dont leave any blank lines behind. I will note that you will likely find a <dict> and </dict> sub section indented inside a section. That is likely where you find the friendly name of your interface. That gets removed with the whole section.

8. You will have to provide a password to allow this to be edited and saved. If it asked for permission to unlock the file, click unlock.

9. After you remove all sections that contain a Thunderbolt interface definition... reboot.

10. After the reboot, insert the Thunderbolt Ethernet Adapter and give it a minute or two to show up in your Network Preferences.

If your worried about this file, make a copy of it before editing.

Below is an example of JUST ONE SECTION i copied out of my file and highlighted where i found the interface name

I hope this helps people out with the issue i was having.. .my Thunderbolt auto detected and i could start using it again.

Cheers

I had a similar problem connecting my 15in mid-2014 MacBook Pro to an Ethernet cable via the Apple Thunderbolt dongle, but I may have stumbled on a workaround. In System Preferences | Network, I created a new location. Still in System Preferences | Network with the new location selection, I deleted all the "services" in the left window pane so it was completely blank. I then clicked on the plus sign at the bottom of the pane, selected "Thunderbolt Ethernet", then configured the IP address, subnet mask, router address, and DNS server address, clicked "Apply," waited a few seconds and...the light turned green, and I was back in business.

I have had exactly the same issue after upgrading from El Capitan to Sierra on my MBA 2014.

Thank you all for the wide range of suggestions for solutions. The heady mix that worked for me:

Plug in Thunderbolt cable with ethernet attached to a tested working port

Apple icon

About this Mac

System report

Thunderbolt- make sure it is listed with Gigabit to Ethernet as a working service.

System preferences

Network

Location

New Location...

Called mine "Thunderbolt"

Deleted ALL services listed

Added new Thunderbolt service (not bridge)

Apply

...

IP address from DHCP router and...

Green light and off we go.

Thanks again.

In my case (cable was detected but did not automatically get an IP number) the problem was Sharing. In the System Preferences/Sharing panel I had enabled sharing the "Display Ethernet" interface. After disabling Internet sharing, it worked fine.

2015-01-24 1403 PM

Problem of last two days that Apple support could not help with:

First, I have been unable to install thunderbolt 1.2 firmware update for the past month from my MacBook Pro Retina. I tried installing from my old MacBook Pro after I recently updated its operating system and apps. It worked! I was able to install the firmware.

Another problem I discovered yesterday was that the ethernet port from the thunderbolt would not connect to Ethernet. It would connect if I used a lighting port to Ethernet adapter from the lightning port on the Thunderbolt display but still would not connect if I just connected the Ethernet cable to the Ethernet port on the thunderbolt (it worked from the old MacBook).

So, I looked at the IP address indicated when the old macbook connected through the Ethernet and MANUALLY entered that IP address into the new MacBook Retinal thunderbolt Ethernet setup and it connected! It has to be some Yosemite software glitch.

Still have no idea why the old MacBook would do the firmware upgrade and the new one would not.

I downloaded an update to Skype yesterday from MacUpdate taking care to access it only on the download link. I received MacKeeper as well surreptitiously. After removing it (a several step process) my system reported that my Ethernet cable was unplugged (although it was connected via a Thunderbolt adapter). I spent much time with my ISP on the phone -- to no avail -- and then I tried your suggestions regarding using Automatic. They worked and now my cable connection is OK. I'm identifying this with the install and subsequent uninstall of MacKeeper even though it was never used because everything worked fine before that. Many thanks and be wary of downloads from MacUpdate (most are OK but it only takes one...)

Thanks TimPetro, you saved my day. My problems did not start after a Yosemite upgrade however - they came to be because I started cleaning up - in my Network Settings I had removed Thunderbolt Ethernet 2, 3 and 4 which somehow had been created over the years.

Reading your fix and other comments it seems to me that the 'old' approach of networking, with locations that you can set, is likely the root of this type of problems. In any case it is not applicable to me, so I removed all locations and am sticking to Automatic.

Thanks again & cheers --Mike

Hi,

I struggled with this issue for some time as well, but arrived at a solution related to a few comments above.

For me, Thunderbolt Ethernet appear 'not connected' not matter which settings I played around with (and despite it being connected).

It ultimately turned out to be directly related to location settings. When all were deleted, and I reverted back to 'Automatic', thunderbolt started working again.

1. Load 'Network' settings.
2. With WIFI enable, click on the 'Location' dropdown in Network
3. Click 'Edit Locations'
4. Remove everything but Automatic.
5. Turn WIFI off.
6. Plug in thunderbolt ethernet
7. Click on Location-->Edit Locations
8. Remove everything but Automatic.
9. Click 'Apply'.

For me, thunderbolt was immediately detected and everything reverted back to normal.

Hope this helps.

Possible solution.

http://plugable.com/2014/10/31/os-x-10-10-yosemite-ethernet-adapter-problems-we- can-help

I had the same issue.

great! this worked! hard to believe it was as simple at changing location to automatic! just spent an hour with apple support and nothing worked... many thanks!

This solved my problem. Over the weekend, I got tired of having to remind my laptop that I was home and created two new locations in Network Preferences. Somehow, that confused my MacBook Pro. So, I deleted my "Home" and "Work" locations and stuck with Automatic. The Ethernet via the thunderbolt display started working again.

Same issue and solution for me. Before that the screen´s logicboard was replaced by Apple, so it seems like they are not even aware of the problem.

I'm considering contacting Apple and asking for a free ethernet dongle, so that I can get the original functionality back of the screen.

I have the same problem with the display Ethernet connection. I spent $29 on an apple help telephone call today without any resolution other than advice to take the display into the apple store for repair! In addition to the Ethernet issue, there is no power coming through the lightning connection to my macbook pro so I have to connect my magsafe power cord to the laptop. What happened to Apple reliability and backing of its products and software! I am very disappointed to have purchased three (3) thunderbolt displays for my macbook at different sites and have such basic functions fail without supported remedy.

the link provide above leads to http://plugable.com/2014/10/31/os-x-10-10-yosemite-ethernet-adapter-problems-we- can-help

...but these seem to be all 3rd party USB ethernet adapters and nothing to do with the Thunderbolt adapter of the thread - or am I missing something?

I have the same blooming problem, it seems to be totally hit and miss whether the adapter works or not.

I thought is was a faulty adapter, so even bought a second one for my MacBook Pro, so a bit more profit for the most profitable company in the world for a non working device. My ethernet cable works fine to an old apple USB adapter but is 90% useless with Thunderbolt.

Renewing the DHCP lease occasionally works, but totally unreliable, at the moment it fails.

Still looking for a reliable solution.

Come on Apple, please sort this out, you have a connector policy of turning everything you can into adapters and dongles rather than building them in, so you end up with a slim laptop and a bag of adapters to carry around, and then when they don't even work - doubly annoying.