Oddly enough, I used to not have this problem. When I opened a picture using Windows 10 Photos, I used to be able to hit Left and Right arrows to view the rest of the pictures in the same folder. But for one particular folder, all of a sudden, it's not letting me do that. It still works everywhere else except that folder. I can't use the arrow keys, and if I do a Slideshow, it acts as if the initial photo I opened is the only photo in the directory. How did this happen????