Ethernet port in Thunderbolt Display connecting intermittently

I had a similar experiance except that my display network got renamed USB Ethernet. I just renamed USB Ethernet to read Display Ethernet and deleted the non-functional Display Ethernet. Seems to have done the trick thus far...

Can you see, in your Network Preferences, under the adapter that is actually your Display Ethernet but is misnamed, what it shows for Hardware?

I am particularly curious what your Bluetooth PAN or your USB Ethernet is showing for Link Speed (100baseT, 1000baseT, etc.) and what your duplex and MTU is.

Looks like this:

This is what mine looked like both before and after I renamed it. The fact that is was connected at 1000 told me it couldn't be the USB Ethernet since it tops out at 100.

And this is mine.

cgq,

Is your display plugged into a 100 meg switch or a gigabit switch?

I asked the technician and he says 100 meg.

please execute such command in terminal:

sudo lsof | grep -i plist

In macs all prefereces are stored in plist files, i thing there is some cache or other file with description of those devices. This is how i found that blued have to be deleted. Maybe there is something more.

At last you might use onyx and remove all preferences and system cache.

I hope this will help.

It did help a lot! In what I am concerned, I will wait until Monday morning to see if it still works, and if it does, I consider this problem solved.

Here is the output of lsof. I hope it helps you improve your solution.

Thanks a lot for helping me!

launchd 1 root 42r REG 14,2 0 4589702 /Library/Preferences/SystemConfiguration/com.apple.smb.server.plist launchd 1 root 43r REG 14,2 607944 4552010 /Library/Updates/ProductMetadata.plist kextd 10 root 4r REG 14,2 2623 34790 /usr/standalone/bootcaches.plist opendirec 13 root txt REG 14,2 308608 4377466 /System/Library/OpenDirectory/Modules/PlistFile.bundle/Contents/MacOS/PlistFile notifyd 14 root 28r REG 14,2 232 86397 /Library/Preferences/SystemConfiguration/com.apple.Boot.plist notifyd 14 root 41r REG 14,2 478 4340847 /System/Library/CoreServices/SystemVersion.plist notifyd 14 root 42r REG 14,2 2445 2194968 /System/Library/CoreServices/PlatformSupport.plist blued 22 root 8r REG 14,2 0 327465 /Library/Preferences/com.apple.Bluetooth.plist.lockfile blued 22 root 9r REG 14,2 0 327464 /private/var/root/Library/Preferences/blued.plist.lockfile loginwind 67 myname 7r REG 14,2 0 474626 /Users/myname/Library/Preferences/com.apple.BezelServices.plist.lockfile loginwind 67 myname 8r REG 14,2 0 475556 /Users/myname/Library/Preferences/com.apple.loginwindow.plist.lockfile loginwind 67 myname 9r REG 14,2 0 475558 /Users/myname/Library/Preferences/ByHost/com.apple.loginwindow.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile loginwind 67 myname 13r REG 14,2 0 775680 /Users/myname/Library/Preferences/ByHost/com.apple.HIToolbox.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile applepush 81 root 12r REG 14,2 0 474723 /Library/Preferences/com.apple.applepushserviced.plist.lockfile logind 202 root 4r REG 14,2 0 327952 /Library/Preferences/com.apple.loginwindow.plist.lockfile Dock 246 myname 21r REG 14,2 0 474608 /Users/myname/Library/Preferences/com.apple.dock.plist.lockfile SystemUIS 248 myname 10r REG 14,2 0 474670 /Users/myname/Library/Preferences/com.apple.systemuiserver.plist.lockfile Finder 249 myname 18r REG 14,2 0 474665 /Users/myname/Library/Preferences/com.apple.finder.plist.lockfile PhotoStre 274 myname 5r REG 14,2 0 2301768 /Users/myname/Library/Preferences/com.apple.iLifeAssetManagement.crash.plist.lockfile Alfred 294 myname 6r REG 14,2 0 946092 /Users/myname/Library/Preferences/com.alfredapp.Alfred.plist.lockfile Mail 322 myname 9r REG 14,2 0 935741 /Users/myname/Library/Preferences/com.druide.Antidote.plist.lockfile Mail 322 myname 21r REG 14,2 0 568270 /Users/myname/Library/Preferences/com.apple.mail.plist.lockfile Mail 322 myname 44r REG 14,2 0 2262534 /Users/myname/Library/Preferences/MobileMeAccounts.plist.lockfile Mail 322 myname 47r REG 14,2 0 475423 /Users/myname/Library/Preferences/com.apple.AddressBook.plist.lockfile Mail 322 myname 50r REG 14,2 0 775680 /Users/myname/Library/Preferences/ByHost/com.apple.HIToolbox.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile iTunes 608 myname 7r REG 14,2 0 475603 /Users/myname/Library/Preferences/com.apple.help.plist.lockfile iTunes 608 myname 10r REG 14,2 0 475606 /Users/myname/Library/Preferences/com.apple.iTunes.plist.lockfile iTunes 608 myname 11r REG 14,2 0 475608 /Users/myname/Library/Preferences/ByHost/com.apple.iTunes.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile iTunes 608 myname 43r REG 14,2 0 924108 /Users/myname/Library/Preferences/com.apple.iPod.plist.lockfile iTunes 608 myname 44r REG 14,2 0 955431 /Library/Preferences/com.apple.iPod.plist.lockfile iTunes 608 myname 46r REG 14,2 0 478791 /Users/myname/Library/Preferences/com.apple.iApps.plist.lockfile System 639 myname 4r REG 14,2 0 522815 /Users/myname/Library/Preferences/com.apple.systempreferences.plist.lockfile System 639 myname 10r REG 14,2 0 775680 /Users/myname/Library/Preferences/ByHost/com.apple.HIToolbox.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile Preview 745 myname 8r REG 14,2 0 606961 /Users/myname/Library/Containers/com.apple.Preview/Data/Library/Preferences/com.apple.Preview.plist.lockfile Safari 812 myname 8r REG 14,2 14850 3950071 /Users/myname/Library/Safari/Bookmarks.plist Safari 812 myname 19r REG 14,2 0 523394 /Users/myname/Library/Preferences/com.apple.Safari.plist.lockfile Safari 812 myname 25r REG 14,2 0 775680 /Users/myname/Library/Preferences/ByHost/com.apple.HIToolbox.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile Terminal 866 myname 14r REG 14,2 0 605556 /Users/myname/Library/Preferences/com.apple.Terminal.plist.lockfile Terminal 866 myname 15r REG 14,2 0 775680 /Users/myname/Library/Preferences/ByHost/com.apple.HIToolbox.96F2CBE1-56C8-5F43-B356-A54200A1FFA8.plist.lockfile

Nothing unusual there.

You might try to use onyx for cleaning cache (http://www.titanium.free.fr/download.php).

I hope it'll help. If not, sorry. This is time when apple developers should do the rest.

The problem is still unsolved. I could not connect to the Ethernet port this morning. 😢

Looks like my problem has not gone away either. I had high hopes at the end of last week, but so far this week my computer is back to its old reliable non-functional self. Guess its time to invoke Apple Care....

The problem by invoking Apple Care is that they will send you to a store to have your screen replaced. Not sure the new one will work better. I spoke to an Apple Care representative that told me a new firmware update should be out soon. That will save you a trip with a heavy box to the Apple Store.

I love it when they try to send me to a store... closest one is nearly 400 miles away 😟 ... their desire to never pay for shipping and my lack of proximity to a store always creates a bit of dilema for them.

I don't really have time to call them this week anyway so maybe they will have this sorted out soon. If not I'll add my voice to the list of folks upset at the performance of my new setup.

Finally broke down and called Applecare this morning. Went through the normal stuff and then they sent me a diagnostics tool to grab all the system info about my MBA and display. Sent them back the diagnostics info and they're kicking it up to engineering to get a solution worked out. I imagine the more people who can take the time to call and send in diagnostics info the easier it will be for their engineers to pinpoint the problem.

Excellent, I did the same thing Monday. Hopefully we'll hear back with a fix.