Wallpapers not saving

Hey Guys,

Seem to be having an issue with new Macbook Pro Retina running Mountain Lion. Added folders dont remain saved in the Wallpapers folder in Desktop and Screensaver and whenever shut down and turn back on, wallpaper will revert to an older one. Not a huge issue, but annoying.

I have Filevault running and wandered if it may have something to do with this?