I use Sparrow Mail on my MBA and love it. I know Google bought them a while back and now they've pulled the app from the app store, so I can't simply download the app from the app store to my new MBP, but I don't want to move on to one of the other mail apps. I tried to copy the app from applications and the folder from library to my new MBP, and while the app opened and appeared to work, it just gave me a "loading" message and none of the mail ever actually loaded. Any idea how to get it to work?