Thanks for this interesting feedback. So it appears Capture NX will not work on the new D850 raw files?
.....
CNX-D(version 1.4.3) is struggling to preview the D850 NEF files.
It says generating preview, but doesn't seem to be able too.
ViewNX2(version 2.10.3) can open the NEF file, but with the caveat that you preview the file in JPG mode(making sure the small NEF icon in the upper LH side is not yellowed).
Of course this means that you can only preview the embedded jpg file in the NEF file, but it still gives you an indication as to how the NEF file has rendered.
We now await the release of CNX-D version 1.4.6, which is the version that Nikon seem to have used to generate jpgs from the NEF files.