Great! Installing the CUDA drivers worked. My mistake: I thought that installing the NVIDIA drivers would be sufficient, but apparently you do need to install those CUDA driver separately. Thank you so much!
p.s. Maybe to help dummies like myself along here, what you could do is list those CUDA ...

Thanks for the reply! Unfortunately that's not the reason. I've tried 17.048, and when that didn't work I thought I'd upgrade to 17.053. Wouldn't explain the non-functioning stand-alone renderer either.

Hi, I'm having trouble getting the demo going on my iMac 27" (late 2012), both as stand alone and as a C4D plugin:

First some data on my setup:
Cuda capable NVIDIA GeForce GTX 680MX
NVIDIA driver 346.03.15f02 (up to date)
OS X El Capitan (10.11.6)
Cinema 4D R17.053 (up to date)

The stand-alone ...