I have tried Media Foundation and both Direct Show Options; installed K-Lite codec pack at suggestion of Tech Support, nothing made a difference.
Am running latest version of Win 10 Pro

Here is the registry settings prior to changing dream (screen is currently black)

Here it is AFTER changing Dream (same black screen)

Like the previous poster said, this was working fine until about 2 weeks ago. I am having this problem on my laptop; on my desktop (same winver) Mars is still spinning and I don't want to risk changing anything!
I CAN change to a Windows static wallpaper - Registry after application:

Stardock static wallpaper works too...
IF I try to change to a Dream, static wallpaper remains as background; here's the Reg after changing to Dream:
