i just got my new macbook and i migrated all my files from my old pb to my new macbook. when i clicked on mail app it asked for an upgrade. I pressed okay then nothing happened. when i try to open mail it opens up the program starts because you could see it in the dock with the light but the message viewer does not show where all your emails should be.... i opened message viewer manually and i could not retrieve emails and or send email.s What could be the problem? thanks!