XBMCNut

Had me stumped for a while before a light bulb went off in my head. I was getting a grey screen with the sound in the background, the GUI would stay visible (i.e. The movie selection screen would not go away) and attempts to do anything else locked up the Pi.

If you run XBMC on the Raspberry Pi, you may have noticed that the SKIN option is now missing at the bottom of the Settings page. This has now moved under the actual Skin selection in Appearance and is not that obvious.