Hey guys, I am just awaiting the arrival of my MacBook Air, and had a question. I have a Western Digital External Hard Drive 1TB. To be specific, it's this one: http://www.wdc.com/en/products/products.aspx?id=430 Now, it's for both PC and Mac, but I've only used it on my netbook, which I just sold. Now, I will be using it on my Mac, but my question is, do I have to reformat it, and if so, do I have to remove everything off of it before doing so? I don't know much about this stuff, so I am at a loss as to what to do. I have alot of stuff on it, over 400GB worth, so I don't really want to have to go through all of that, if I don't have to. Any advice?