Hi guys,
as reported in this other discussion, Maxon reported an issue with Mac Os Sierra 10.12.5 and Nvidia drivers that blocks C4D R18.048 to correctly startup
I have installed Sierra 10.12.5 on my Mac Pro, and I can confirm that the solution of removing only the libosmesa.dylib file from ../resource/libs/osx/mesa to solve the issue of starting up R18.048 correctly.
I had not to change the Nvidia drivers, and my 1070 works as expected.
It is not perfectly stable, I had one crash while moving objects in LV, but it should be usable until Maxon and Nvidia solve definitly the issue.
Happy rendering,
ciao beppe