I've been having a strange problem ever since the rollout of Windows 10 to both my SP3 and SP4 (and Lenovo laptop). I have around 500 pictures stored locally that I use as wallpaper backgrounds. I have the settings set to slideshow and have selected the folder, however, it consistently resets to the ...\DesktopBackground folder with a subset of around 20 of those pictures. I've even tried moving all of the pictures to that folder and it still doesn't show the full set. Any ideas?