On a mac, the operating system is responsible for the thumbnails of camera raw files, like the nikon D810.
The adobe software, just allows adobe applications like photoshop and bridge to see and process the camera raw files.
Which version(s) of mac os x do you have?
Which version of photoshop are you using?
Thanks for that info. I have been using all updated software for both my imac and programs. I have creative cloud for photoshop and lightroom and I have versions 5 for both and my imac is currently using yosemite. I can see the files with no problem in both lightroom and photoshop but cannot look at them as thumbnails on my desktop but was always able to in the past with other cameras. Any suggestions? It's not the biggest deal but I was just curious if there are fixes for this...
On mac os x 10.10.5 Yosemite i can see the thumbnails from a nikon D810 camera raw file on the desktop and in Finder.
Macs use the Digital Camera RAW Compatibility Updates to generate the thumbnails on your desktop and Finder.
Is your mac updated to os x 10.10.5?
Apple menu>About This Mac
Also, Apple menu>App Store>Updates and see if there are any updates you haven't installed.