How to manage media files?

[Snafuy]

I transplanted the SD card from my old phone (4.0 ICS) and set it up as "Portable Storage". The Moto G copied all the audio/image/video files onto internal storage and won't let me delete them. I want to reserve internal storage for apps and keep my many gigs of AV on the card. What do I do?

BTW, it also duplicated all of the music files on the SD card, so there's two copies of each song there (plus another on internal storage).

 

[acejavelin]

That seems very odd... Setting up the card as portable should not have copied anything, only indexed the files on the card for quick access.

Are you sure the files where moved? What is the path to a few examples?