This happened to me also. If you press CTRL+ALT+DEL and then ESC key you can see the desktop normally. I set a black jpg as wallpaper
maybe it's because the resolution of the solic colour is to low. There is no reason to put high-res solid collor backgrounds in windows, so MS may have used like a 1 x 1 image. Or it could be that solid collor backgrounds have an other extension, like bmp instead of jpg...
Not sure what you're wanting, wasn't (isn't) it just a little bug when using a solid colour background and Aero. As has been said before if you're using Aero and want a solid colour background just use a solid colour background image, that's what I did, sorted.
Could be, beause that "Custom"-made don´t increase the delay on welcome screen for me ... (simply made a 1280x800 .jpg picture with solidcolor) The "build-in" backgrounds with solidcolour are causing this error to me ... strange ^^
I think the hole point in this post is to figure why is that happening when wasn't supposed to happen!