Huge difference between Capacity figures and Mac - help

I moved my entire itunes library to the WD MyCloud and it was 265GB, however, I checked a couple days ago and the Capacity on Dashboard stated 540GB of music! When I used my iMac to show the size of the Music folder I have on WD MyCloud it states 303GB.

I’m really confused as I want to move the entire itunes to the Mac but don’t want to move 540GB and also, why has it more than doubled?? (I’ve checked folders for duplicates and whilst some exist, I can’t see enough that it would have doubled the entire library) - asny suggestions - is Capacity accurate??

Hi Porkpie74, the dashboard will show all the music files saved on the My Cloud, not just the iTunes library, do you have any backup programs that might be also backing up files to the My Cloud?