I’m so glad to see that the background image previews with Active blur selected for Wallpaper type is also all white boxes instead of the preview of the actual image for you as well, because I thought I was going crazy and figured I’d just live with it. Any ideas why this happened? If I switch Wallpaper type to Image all the background image previews load just fine, but not when Active Blur is selected. I have similar screenshots posted in another topic here: KDE Active Blur wallpaper plugin appers broken, black desktop background - though I fixed the issue I was experiencing on that post.