Ethernet does not work when plugged into the back of my new Thunderbolt display.

What kind of Mac (also what year is it) are you plugging your TB display into? What are you plugging the Ethernet cable from the TB into (make/model of the switch or router). Are you using Catagory 6 Etherent cable? Have you tried another cable? Do you get a link light when plugging the Ethernet cable into the switch or router?

Let me know.

Another place to look would be in System Preferences/Network. I don't have a Thunderbolt display so I don't know what shows up there but it should be there. You might have to select it as your ethernet source or do something to set it up there.

I have the same issue. I have a 2011 MBP 17' with the most up to date version of Lion. Not sure what to make of it.

Okay, I figured it out. Plug your ethernet directly into your computer. When you launch Network Pref you will see a comment, "Two new network connections detected, display ethernet and display firewire." YOu will then need to "turn on the display ethernet through the network settings pref pane under Display Ethernet. After you do that you can now plug yout ethernet directly into the Display and away you will go. Let me know if you need me to clarify. One final note, I changed the location under network from Automatic to 9/29/11 8:55 pm)

Enjoy.

I just bought the thunderbolt display for connection to my new mini 2011 server (using lion server). Same ethernet cable works when attached to back of mini, does not on back of display. I have reviewed the network connections under network connection program - states is not working when cable on back of display.

Ideas??

PS Yes, I have checked apple updater and new firmware update for thunderbolt display done.

Jamie,

Here is the easy fix. Download the Thunderbolt Display firmware Update and boom everything is working again. Disregard by other post and just apply the firmware update and you will be back in business.

My Thunderbolt Display came with the updated firmware already installed, and I still have the same problem.

Initially Ethernet worked just fine, but lately it isn't recognized as even being plugged into the back of the display.

Hi Will,

What kind of Mac are you plugging your TBolt display into?

Mine is a Macbook Air, 13" i7 running OS 10.7.2.

This is a known problem that has been around for months...

https://discussions.apple.com/thread/3517737?answerId=17772297022#17772297022

Problem solved?

My problem seems to have been resolved by the simplest of things... turning off WiFi.

If WiFi is turned on, the Mac seems not to recognize the existance of the display adaptor. If I turn it off, voila!, it sees it.

It seems to have a similar problem deciding between using my mobile hotspot through bluetooth and WiFi. When both are available, it defaults to the slower of the two.

Far from being solved! Switching off wifi doesn't fix anything. The display ethernet stays inactive and the only way to fix it is to restart the computer.

The only "solution" found to date is a cold restart of the computer. This suggests to me that it's not a problem with the display, but in MacOS X.

@Will.G - post 6 mars 2012 09:29 (in response to storiestold)

Thanks a lot for providing this clue !

Tunring WiFi off and unplugging and plugging back the thunderbolt cable solved the problem for me.

Quick update on my side. I followed the advice of John May here:

https://discussions.apple.com/thread/3524526?answerId=17541133022#17541133022

And deleted my /Library/Preferences/com.apple.windowserver.plist (do that in single usermode). Everything has been working perfectly since then (more than a week now).