System files and folders are hidden files and folders that your operating system uses to keep track of information such as display settings for a folder and previews of image files. These files aren't necessary for backing up your data. The benefit of not copying them is that you save space in the location where you are backing up your files. By default, these files are not included.
Examples of these types of files are: *.tmp, *.bak, *.log, thumbs.db, ehthumbs.db, RECYCLED, RECYCLER and System Volume Information.
DroboCopy Overview
Creating a New DroboCopy