WD eats up additional space

Between my PC System and My Book Essential appear tremendous space differences.

At this point the ‘used’ space for movies, pictures etc are exactly the same however, my PC shows for additional space used ‘System 71.7 GB’ but My Book shows ‘Addtln Files 648.8 GB’ .

Why does My Book Essential eat up almost ten times the storage of my system on the PC ?

In addition to my PC system what is so voluminous in My Book ?

What am I doing wrong and how can I correct it ?

For you experts this would probably allow for a quite simple answer however, since I am a Newbie I would appreciate your detailed advise.

By the way, just a few days ago I had posted a (probably fairly simple) question about how to convert My Book from automatic backup to copy and paste only. “ragdexx” was kind enough to post a quick question to my ‘How to’ enquiry but when replying to his points I never heard from him again ?! Anybody ??

Any files that are manually added to the drive will be categorized as additional files

they can be transferred from any computer and not just the one that is currently plugged in

that’s the reason why you will see a difference

Thanks for your advise !