So I had my MacBook Pro plugged into an external monitor.. and I unplugged it from the external monitor, and the background still appeared on my macbook pro.. well.. I close the lid, and later on I open my macbook, only to find my background has disappeared.. it's just white. also, the dashboard background had also disappeared.. everything ran fine, I just couldn't change the background, or lack thereof, and the background that was there wasn't showing up.
EDIT : Restarting brought the background back up.
EDIT : Restarting brought the background back up.