Q: USB 3 - has it changed functionality ?

I use my Macs alongside my Nikon cameras (D700 and D800)

Previously (last year) I have been able to shoot in the studio using "tethered mode" which enable me to operate the camera from the Mac running Adobe Lightroom.

I could see the images as they came in and even operate the camera from the computer.

Now, however this function has vanished.

My camera no longer shows up in Lightroom

Searching around the photography forums turns up several posts about this issue and a lot of them point the finger at the El Capitan update.

As usual all the companies point the finger at someone else when compatibility issues arise.

I have Nikon cameras Adobe Lightroom, Mac computers, Tether Tools USB 3 cable and all seem to be ready to blame someone else for the sudden lack of function.
Anyone heard anything about this ?
Possible fixes ?

Pretty annoying how functionality gets eroded.