I migrated my son's college PC to his Macbook Air and, now that the migration has finished, the desktop he gets after logging in is just a black background and all the icons showing are a mixture of some (not all) of his PC desktop icons and some (not all) of his Mac desktop icons. It should just be the exactly the same desktop picture and desktop icons as on his migrated PC, right? How do I fix this? Any help would be greatly appreciated.