Directory Opus 12, Windows 10 (64-bit).
In trying to use the Viewer/Slideshow by selecting a picture folder I get screen message "Unable to load pictures [lists them], Access is denied".
Each picture can be viewed in Viewer Pane, as a thumbnail in the file Lister, and if I open the picture folder, select a bunch of the pictures, then use "Slideshow" this works.
If I use Windows 10 "File Explore", select the same picture folder, Windows 10 has a tab that occurs "Manage" (File, Share, View, etc.) and then I select slide show the pictures are presented in a slide show.
I checked with my laptop as it just upgraded from 11.x to 12.2 and the same thing happens.
I did search on "access denied" and read most of the 2016 and some of 2015 similar issues of "access denied" (257 of them) before posting to see if there was similar problem, I saw some that were close; looked to see if any of those solutions might apply; none appeared to.