Thunderbolt ethernet does not connect when plugged in.

I resolved the issue (with help of R. Singh). This is how I did it:

1. Unplug the Thunderbolt Network adapter (and / or Display adapter). This will not work if you keep the Network or Display dapter plugged in while doing the next few steps.

2. At the top main menu, click on "Go" and then "Computer". Navigate to: Library > Preferences > SystemConfiguration and drag to the trash the file "NetworkInterfaces.plist"

3. Restart your MacBook Pro and log back in. Once you’ve logged in, connect your Thunderbolt Network adapter again.

4. Go to System Preferences and click Network. If you see Thunderbolt Ethernet in green, you’re all good. Otherwise, click the plus + button at the bottom of the list of network interfaces and create a new Thunderbolt Ethernet interface.

I have the same problem. It started after applying the latest firmware update. In order to recognized that an ethernet cable is plugged-in, I need to restart the rMBP. Before the firmware update, I could connect the thuderbolt addapter at any time and it recognized that there was a cable connected. I will submit a bug to Apple.

brianfromwaverly,

Thank you for your reply. Looking over the adapter:

• RJ45 port looks good - all pins are straight and appear clean.
• Thunderbolt connector also looks good - all pins are clean and straight
• Cable connecting the thunderbolt connector and RJ45 port is in excellent shape.
• Connector on the MBP Retina appears clean and in good shape (I don't use it often)

Here is what I have done to test (keep in mind - the adapter appeared to be working without issue prior to the Mavricks upgrade):

• Plugged it into my non-Retina MBP (running Mavericks) - it works consistently without issue
• Wiggled the connectors a bit to see if it would connect
• Tried a different port on the switch
• Tried a different switch
• Tried a different Ethernet cable
• Tried both Thunderbolt ports on the MBP Retina
• Removed NetworkInterfaces.plist and rebooted
• Removed the adapter in System Preferences -> Network then re-added
• Tried this: https://discussions.apple.com/thread/5484290. After making this change, the adapter started working for a short while (as described in my original post). Subsequent attempts did not work.

Thank you again for your help!

I've had similar problems. Especially in hotels, the wifi can be slow or the signal is weak. I've tried connecting my 2012 15" Retina MBP with ethernet using my Thunderbolt adapter, however I have never been ablt to connect to the internet through ethernet. It will show an active ethernet connection in Network preferences, but no internet. I've tried reboots to no avail, and when I tried installing the Thunderbolt Software Update (1.2), I get an error message that it is not supported by my software??? My old 2007 Macobbok connects via ethernet no problem. I spent $4k on the rMBP and now can't do what I used to do.

I have the problem now out of nowhere. I have never had a problem with the adapter until last night. Now it will show that it is connected and display an IP address, but no internet or access to anything on my network. Really quite annoying there is no fix for this.

Good thought Brian. I tried it, but it didn't work. It was encouraging to hear that you were able to mess with some settings and get it working again, so I dove in a little more. Low and behold, I deleted the Thunderbolt Ethernet from the Network page, then applied, then added it back, clicked Apply again and it ended up working. Something must have corrupted in the driver and just needed to be reinitialized. Oh well, hope this can at least save someone a headache down the road.

What if you don't even have the Thunderbolt Network adapter listed in the list of Network connections. All I have is WiFi, Bluetooth PAN & Bluetooth DUN, and in the bottom section there's VPN, PPPoE & 6 to 4.

I have a Mid 2012 with Retina Display Mac Air with 10.8.3 Build 12D78 installed for OSX.

If I goto the About this Mac and More Info and click on the Thunderbolt section it shows that I have the ethernet adapter plugged in and if I remove it and then refresh it goes away and then plug it back in and refresh comes back to the list. Below is what it's showing under More Info - System Info

Thunderbolt to Gigabit Ethernet Adapter:

Vendor Name: Apple Inc.

Device Name: Thunderbolt to Gigabit Ethernet Adapter

Vendor ID: 0x1

Device ID: 0x8003

Device Revision: 0x1

UID: 0x0001000200B220F0

Apple Serial Number: DTN237407WEDWKHB5

Route String: 1

Firmware Version: 5.5

Port:

Status: Device connected

Link Status: 0x2

Port Micro Firmware Version: 0.0.8

But I can't see any Thunderbolt Adapters listed under Network Connections and it won't connect to the router since I don't have a network connection listed in my Networking section.

I have this exact same problem.

To summarize, I am using a cable modem (RCA DHG536) on Comcast. I am running MacOS10.8.5. My thunderbolt ethernet has a "connected status" under System Preferences> Network. Network preferences says I have an IP address (although it does not list any Router or DNS server)). And when I try to access the internet, it says I am not connected to the internet. The same cable modem works on MacOS10.6.8 and Windows 8.

If I follow the instructions under Network Diagnostics, there is no resolution or change.

If I run Network Utility, I can see packets being sent and received (a few) and link status is active as well. But no internet connection.

I have meticulously tried the solution proposed by JediMindTrick (which worked for him and muradn79), but it doesn't work for me.

I have meticulously tried the solution proposed by NuevaYork (which worked for him), but it doesn't work for me.

I tried creating a new location (as worked for brianfromwaverly), but I get the same problem as when location is "automatic".

I did not understand Hank7's suggestion about changing the environment profile. When I googled (mac os x environment profile), I didn't get much except references to environment variable, which didn't seem relevant (or I couldn't see the connection). So I did not do anything with my environment variable (which I have never done anything with in the past either…)

Does anybody have any other ideas?

If not, does anybody have any suggestions about other places to look for answers?

Thanks!

Since upgrading my mid 2012 MBP Retina to Mavericks (10.9), I have been experiencing the same issue. Everything is plugged in, but the Network System Prefs panel shows "Cable Unplugged". Ethernet cable is plugged into a known good port on the switch. Plugging the adapter into another (older) MBP works without issue. I have tried deleting NetworkInterfaces.plist - issue still exists. I removed the adapter in the Network System Prefs panel then re-added. It came back online for a short while (about a half hour) then it cut out again. Haven't been able to get it back online since. I too am looking for any ideas or suggestions. Thank you!

guys, its hard to believe apple would design something that does' t work. This adapter is gigabit ethernet right.

that means you better have at least a cat 6e cable for reliable connections. i've seen this many times at work.

what could be happening is when you plug your cable in if its connected to a gigabit switch it negotiates communication

speed. it only takes a couple of ethernet packets for both ends to say "yes i can comm at a gigabit". then if you have

a crummy cable (less than cat 6e) when you start communication on the web you are getting near end and far end

crosstalk. the computer is so busy asking for retransmits that you don't get any bandwidth. I see it at work all the time.

back you adapter off to 100mbit and if thats the problem it will start working.

Similar/same problem: Ethernet-Thunderbolt dongle plugged into Macbook Pro. Home LAN going through two switches and a router to get to a cable modem. In "Network" a green dot displayed for the dongle, but there was an intermittent message indicating a (nonexistent) IP conflict. Also, ping failed. What worked for me was to turn off wireless, get rid of old locations, start a new one, and then go through building the connection. When that didn't work, the screen message was to restart my router. I restarted all switches, the router, and the cable modem (possibly overkill to do everything, but it was easy and it was a way to reset all devices)--and waited. After a couple of minutes the Ethernet/Thunderbird lashup made it all the way through the milestones, and the connection was finally good.

This problem and its close relatives have been noted in forums for some years. It appears that it is not terribly hardware-specific. It also doesn't seem to depend on the version of OS X (at least within the past few years)., and may not be triggered by firmware or driver updates.

hwi brian.. same problem here. I have a MBP Retina 15. very simple fix. In network preferences add new connection and select Ethernet thunderbolt. hit apply.

afterwards turn off wifi and like magic, ethernet will connect.

Gabriel

Thanks for all the suggestions! I was able to resolve this problem by entering Recovery Mode, turning off WiFi, testing that the Thunderbolt to Gigabit Ethernet Adapter was working in Recovery Mode, then selecting the Recovery Mode option for re-installing OS X. My Mac was back working in under 45 minutes, with all settings and files intact. Except now with wired ethernet working properly. Details below. Kudos to AppleCare phone support!

What didn't work for me::

I had first tried the solutions offered in this thread and in similar threads. None helped significantly. The only thing that had helped at all was deleting files from /Library/Preferences/SystemConfiguration -- sometimes deleting just NetworkInterfaces.plist, sometimes all files except com.apple.Boot.plist -- and restarting. Unfortunately, this solution worked only briefly, for one (sometimes two) plug-ins of the adapter. After that, the the Network pane reverted to not noticing the Thunderbolt-to-Ethernet adapter at all, even though one could see (via dmesg) IOThunderboltSwitch messages for each physical plug/unplug event. If I wanted to use wired ethernet, I would have to delete the files again and restart the machine. This process worked reliably, but it is not something you want to do several times a day as you move around an office, attend meetings, etc.

My system/network:

I have Mac OS X 10.11.3 installed on a mid-2014 Retina 15" PowerBook. The Thunderbolt-to-Ethernet problem started around when I upgraded to 10.11.3, or possibly when I upgraded to 10.11.2 . I use wired ethernet pretty normally: I plug in an Apple Thunderbolt to Gigabit Ethernet Adapter directly into my MacBook Pro, and plug a standard ethernet cable -- a cat 5e/RJ45 cable which works fine at gigabit speed with other laptops -- into the adapter. The ethernet cable plugs into a simple unmanaged gigabit switch, which is plugged into the building network. I tried multiple genuine-Apple Thunderbolt to Gigabit Ethernet Adapters; all showed the same problem.

What worked for me:

1. Back up your Mac with Time Machine (just in case).

2. Shut down your Mac.

3. Unplug Thunderbolt-to-Ethernet adapter.

3. Enter Recovery Mode: hold down cmd-r, press power button,

don't let go of cmd-r until you see Apple logo and a progress bar.

4. Turn off Wi-Fi: use icon and pull-down menu in upper right of screen).

5. Test internet connectivity: Select "Get Help Online". Once in Safari, enter the address of a website or two (apple.com, nyt.com) and see if they load and if links can be followed..

6. Select "Reinstall Mac OS X". Be prepared to wait a bit, this took me 45 minutes, and that is with the usual SSD in my Retina Macbook and a very fast near-Gigabit internet connection in my office, although I don't know if much network was used.

7. Log in and plug in Thunderbolt-to-Ethernet adapter. Check Network preference pane to see if all is well. Try an unplug/wait-a-few-seconds/plug-in cycle. Try another one. With luck: rejoice!

I imagine the OS reinstall would take longer on Macs with spinning hard disk instead of SSD.

Hope this helps!