The duplicate files are mostly the music, video and image files, which the iTunes synced with your Mac might be saving them from your Mac memory directly without your knowing. Now duplicate files stored in iTunes can be a real headache, and you seriously need to do something about it as quickly as possible. But when the files are stored in a server, duplicate files can take the space for which you have to unnecessarily pay, whether it is iCloud or iTunes.
Duplicity of files is one of those cumbersome which takes a lot of space of your system memory.
