Ethernet not working on Yosemite

[Olbert000]

My ethernet cable internet has stopped working.

I normally connect my 2013 MBP to the internet via my home wifi network, however I often like faster internet for downloads, games, etc and connect using an ethernet cable and a thunderbolt adapter. It has stopped working. Normally I have to turn off the wifi to force it to use the ethernet (not sure why!?) but that makes it work. This time that doesn't work and diagnostic/assistant doesn't help either.

The wifi works on the same network. The ethernet cable and port works on a different laptop (I haven't checked the thunderbolt adaptor because it's not a mac).

Why would it stop working (I haven't changed anything)? How can I fix it?

 

[Fishrrman]

Simple question (perhaps you've already done it), but...

... have you tried rebooting the MacBook?

 

[Olbert000]

Simple question (perhaps you've already done it), but...

... have you tried rebooting the MacBook?

Yes - I've tried rebooting it.

Interestingly the last time it worked was when I was on Bootcamped Windows 7. Could that have messed with any settings?

 

[blueroom]

Are you using the Apple GigE Thunderbolt adapter or a 3rd party?

 

[Olbert000]

Are you using the Apple GigE Thunderbolt adapter or a 3rd party?

Apple one.