Help me with Migration Assistant?

[W]

Hi I just got a new Macbook Air to replace my Macbook Pro from either 2010 or 2011. I'm trying to move all of my files from my Macbook Pro to my Macbook Air using the handy app called Migration Assistant. I've tried using it twice now, and both times it's usually taken a while so I leave it on overnight. However, both times that I've used it, it just stops loading at a certain point and doesn't continue loading, usually when it reaches the point where it says that the download will be complete in less than 2 hours. Is there anyway I can fix this? My Macbook Air has enough memory for all my stuff so I don't think that's the problem. Any help is greatly appreciated.