Build 10537 (64 bit) same was true in prior builds.

I use the Pictures folder for a random slide show as a screen saver. Every now and then (I cannot intentionally duplicate the issue), the screen saver will start, go to a black screen, then state there are no pictures in the Pictures Folder.

This is incorrect, and in a screen saver preview, the pictures will display; and most often they also display during a normal screen saver engage. It appears to be a random glitch.

I also note that in prior Windows OS, such as 7, the pictures display immediately when the screen saver engages; in Win 10 the screen will remain dark for a longer periods prior to the pictures beginning to display.

Other screen savers, such as Mystify, begin displaying normally.