As the years go by and files get copied and pasted between folders on your computer, unnecessary duplicates (and sometimes even triplicates) of files will add up.
To track all these space-wasting files down, you can use the built-in Windows search function, but you're better off using a dedicated search tool like the handy AllDup program.
This small search tool will find all the duplicate files on your computer and list them for you by size, name or creation date, and also lets you delete them.
AllDup is available free of charge at alldup.de
and runs on all Windows versions from Windows XP to Windows 10. – dpa