I have bought an Apple Thunderbolt Ethernet Adapter and can't seem to get it to work.
It simply does not appear in the Network section of System preferences, even though the System Information dialog shows it is connected.
Here is how it looks: http://imgur.com/a/WUfbD
I have tried everything from here already.
I have el capitan and a retina macbook pro.
EDIT: I took it to the store and they confirmed it works fine. So it seems to be a software issue.
EDIT2: I solved it by reinstalling from scratch.