Thank you for the link - I did follow the steps mentioned in the article with no luck in changing the tethering from my MacBook Pro.
The odd thing is, when I do turn on my D7100 and it has a SD card with some photos, LR 6.3 recognizes that I have a camera attached and immediately opens the import window ready to import some pictures. It makes no sense that LR sees the camera when attached via USB cord to import photos but does not see the camera when I ask for tethering.
Something very odd is going on - especially since this is not the case when I attach my camera to my iMac 24" .
I hope someone can diagnosis this and find a solution.
I suspect there is some kind of settings in your Macbook that is preventing Lightroom to do tethering.
I would suggest you to reinstall Lightroom on your Macbook and check if it helps.
Thanks. I also feel it has something to do with my MacBook Pro which is 5-6 yrs old already.
BTW I have reinstalled LR6.3 with no change.