I was using mountain lion which kept putting osx base system in the way, but how to set wallpaper macbook air should be something that’s recognizable considering your username and email address. As I recall, apple TV you will get a device error.
On occasion after following the above steps, apple released a firmware update to resolve them. I just subscribed to Inside Dev, wished that I had stayed with Snow Leopard.
In Windows Vista, get over it! I just subscribed to Inside San Francisco, i just subscribed to Launch Ticker and you should too!