Windows Vista Backup Utility Questions

[KHC]

I am currently running Vista Home premium and using the backup utility. I am perplexed as to how it backs up. I have used this utility since upgrading in Nov 2007 and currently set it for weekly backups. I also have it set to backup documents only (which includes music and pictures). I have a 500 GB external hard drive as its destination. It shows I only have 42 GB left! My document, music, and picture files (the rest are minimal) add up to 80 GB at the most. I thought Vista Backup was an incremental backup system (just adding the new stuff). I know the files are being compressed, as they are all in zip files.

Why is it taking up so much of my hard drive, if it backs up incrementally and it compresses?

Thanks

 

[kemical]

Looks like its backing up the whole disk image every time... I'm sure the back up utility in the home premium version deosn't work like the one that comes with Ultimate. In other words you'd be better off just making sure you create a 'system restore' copy every week. Vista does this anyway when installing new software but if you haven't installed any for a while you will need to create the system restore copy as I mention above.