Backing Gmail stops after a few Gb's

Backing Gmail stops after a few Gb's

So far, I've been using Gmail through their web interface exclusivly. Then, since I often work without a network connection, I decided to get it all into outlook (v2007), so I can access it offline. I knew I could've used Gmail's offline package, but I prefer outlook, as it being a "normal application", and I'm used to it more than to these "new applications".