CloneSpy can help you free up hard drive space by detecting and removing duplicate files.

Duplicate files have the same contents regardless of their name, date, time and location. It can find files that are not exactly identical but have the same file name. Perhaps you have different versions of a file, and you want to find all of them and remove the older versions. It can also find zero length files. These are files that have no content.

With CloneSpy you can process files which

are duplicates
are duplicates and have the same file name
have the same file name
have the same file name and (approximately) the same size
are zero bytes long