I do not believe the last version of ViewNX2 is compatible with a D850 or even the D810.
Dave
As said before, ViewNX2 will keyword and rate later model camera NEFs even tho it's officially not supported.
I can confirm what Øivind said that D500 NEFs also work fine(which would be expected)... and luckily he also explained that direct RAW viewing mode needs to be turned off to preview the files too in VNX2, otherwise it simply says unsupported file. Thumbnails work fine tho.
IN my last post I mentioned that it was sometimes flaky in it's operation, but this was my error in what I attempted. In Windows Explorer, with the dialogue box open on the NEF properties, I made mistakes in trying to add(edit) tags/keywording, which I've done many times previously but yesterday, somehow, managed to get myself tangled. It works fine(as I suspected) but I simply clicked onto the wrong area of the tag info in the Properties box. ie. my error.
I was going to reinstall the codec thinking something was wrong, but it wasn't needed.. my error.
Tried again this morning, clicked correctly added another test tag to the D850 NEF.
Theoretically you don't need VNX2 at all, just the codec and Photo Gallery and Windows Explorer to tag images with searchable keywords.
I just find VNX2 to be a bit more useful in some ways. And while having the ability to add/edit keyword tags directly via Windows Explorer is handy, it's clunky compared to both VNX2 and WPG.
I also forgot to mention that if you do edit or add keyword tags via Windows Explorer, it also uses a system of dropdown suggestions tags once the first letter of that keyword is entered. I'll attach a screencap of this process too. Very random and strange suggestion tho .. I typed a 't' to use the term "test tag Windows Explorer", because I've used this term prior on other NEF files, but the results for the suggestions list range from anything to anything, if there is the letter 't'
anywhere in the tag line!
WPG is a lot more sensible in that it will suggest any previously used keyword tag line that begins with the letter 't' .. which makes more sense.
I think it's still a handy feature to have in Windows Explorer even tho it's clunky ..
Click the tag line you wanted, click ok .. done.
When you add non archived tag lines, the process needs to be to click Ok, then click apply for it to stick to the NEF file.
AND! ... it gets me wondering, how/why can very old, long superseded software, using thirdparty intermediary application, add/search/use tag data embedded into a proprietary file format .... yet Nikon can't seem to do it anywhere near as seamlessly in any of their software offerings ... ever!
I hope that one day NXStudio will come good in some way at least where one has the ability to add keyword data into the raw file directly. This is simply my preference in the way I like to archive my images.
I had hopes for it when I noted the option to embed the edits into the file .. but the process it uses(or trying to use) simply isn't doing it well.
I've been using this system for a good 8 years or so now, never had a real issue with it .. sometimes have a small stumble with the codec not clearly working perfectly, but always fixable with a reinstall of the codec.
But then again, those small stumbles may also have been my fault in that I may have made some small error step or the PC may have had issues(which it does now) .. but anyhow, still works and much farther into officially unsupported territory than I expected it too when I first began using it.
IIRC VNX2 was officially made redundant in 2014 along with any updates/upgrades to CNX2, with the release of CNX-D.
Many cameras later and VNX2 still operates well as a viewer/tagging system for non supported camera NEF files.
I still think VNX2 is the fastest NEF file viewing application available, and by a long shot too. I reckon I've tried them all to be honest.
FSViewer(Fastone) also gets a recommendation(as a viewer only). Also very good to quickly edit jpg files with instructional addendum .. not so much actual pictorial editing tho.