The fix is described in Launchpad here, but I'm going to summarize it because it's a little spread out in the comments to the bug.
- Right click on the desktop and select "Create Folder..."
- Double click on the folder you just created
- Navigate to "/usr/bin/desktop-switcher" and run it
- Switch back to the UNR desktop
- Now navigate to your home directory
- Show hidden files (View-> Show Hidden Files, or Ctrl-h)
- Delete the .gconf, .gconfd, and .config folders
- Log out and log back in