I've been using Time machine since the day it came out, about 2 years ago, I think. It's connected to a 500GB Time Capsule. Works great. However about a month ago I noticed it backs up large files almost every time. I mean anywhere from 80MB to 1.5GB or 2GB. I'm sure this is related to my mail.app that is always running (and has lots and lots of emails - with attachments - in it). But I would think it would only be backing up the stuff that's changed, right? I'm not doing any large downloading, video editing, or working on files large. Any ideas? Sometimes, however, I do view videos online (streaming). Might this be what's being backed up? The casche of those videos, or something like that? FWIW, I've eliminated the following folders from being backed up: /Desktop, /documents/Microsoft User Data /Microsoft User Data /Movies /Podcasts /TV Shows Thanks!