OK, long story short, Ethernet adapter worked fine the last time i was in Dallas around June/July time. I've since updated/graded the rMBP to El Cap and the first time i came to use it last friday it wouldn't work no matter what i did. So i ran the update again last night so I'm now on 10.11.2. My Yosemite laptop, (10.10.5) is also not working. I've done all the usual things, deleted the locations (so i only have Automatic left now), I've made sure the adapter is in Link-local only mode for IPv6. I've removed the bridge and device and re-added. If i look in system report, it does show the device is present and states it as active. If i remove the device, it also see the device has been removed. I have a direct connection to an Apple Time Machine, the cable is fine. I've tried my other two rMBPs, again, same thing. they all see the dongle, but nothing works. I've renewed the lease, I've rebooted more times than the whole of the windows install base!!!!! I've tried moving ports, nothing. Ive created a new location and added only the thunderbolt bridge and adapter to the location - nothing, still shows as active in system report, but wont go green. I see this is a if not common problem, a well known one lets say, but i can't get this PoS to kick back into life. If all else fails I'm going to take the dongle into apple and see if they can check it.. Any suggestions welcome.