Undup

Undup - this simple free tool allows you to visualize the contents of your hard drives, external drives, DVDs, USB sticks, etc. to see what's taking up space. It can then search for duplicate files and directories and show you which are outdated copies and which are the latest versions.
When comparing two objects (files or directories) there are 4 possible results:

• They are identical
• One is an older version of the other
• One is a newer version of the other
• They are different.