These are your files. You know which to delete and which to save. If you don't you move to the next duplicate.
In closing, we only lose what we don't backup. If you don't have a backup copy on CD/DVD/otherplaces then you may not have been told about backup.
Has anyone used this? My question is when you scan for duplicate files and there are alot of them. How do you know which duplicate file to delete? Does this product know which is the newer file?