Delete files

Smartware keeps adding files to my backup when I temporarily place them on my desktop, example such as photos when I want to take them off my camera and put them on to a USB only - How can I delete these files from the My Book backup file as I don’t want them backed up. Tried deleting them from the backup drive but the folder is still visible.

I have a 1TB My Book drive running on PC 3.0 dual core Vista.