I have a laptop with a 4K display and DPI scaling set to 250% (default), and whenever I change this to any other value and restart to fully apply it all of the icons on the desktop, taskbar, start menu, in folders and basically everywhere disappear (except for some windows icons like Edge browser and Cortana).
Changing the DPI back to the default 250% and restarting makes the icons appear again but I need to change the DPI in order to use an external display without scaling issues and blurry text.