So I'm taking my new macbook air to the shop and the seller is probably going to replace it with a new one (camera isn't working). My question is migration. They'll take the one and give me another, without my being able to use migration assistant. Will time machine via an external drive be able to do the same thing? I'd like to avoid having to do all of the downloading, setting up, etc, that I just did a few days ago. Anyway to save me from this without migration assistant? e.g. files, applications (particular MS office since I only have 1 license), touchpad settings, etc.