Well, after purchasing my mBA and putting everything I would on it, including VMware, Office, other apps, etc etc etc, well I made a backup about 2 weeks ago. The time machine created a folder with the date on it and everything is golden. So I plug in the external HDD to make another back last night. From what I could tell, its as if it was backing up the whole HDD again, from the amount of GBs left. I thought its supposed to only do incremental backups, not a "from scratch" backup. Anyhow, I let it continue, and at the end I end up with another folder with yesterday's date and "revision number". So now things look like this for example: 2011-28-07-12566 2011-13-08-14500 Now, does that mean I can delete the first folder and just keep the last one? Then, when I added some small files, it seems that when the next backup was ran, it backed up a lot more than the size of those files. It seems it was backing up Gigs of data, and am not really sure why. At some point between yesterday and today, I ended up with 4 different folders like this for example: 2011-13-08-14500 2011-13-08-15600 2011-13-08-16900 etc etc Can someone please explain how this thing is really supposed to work? Thanks.