Default [Q] Samsung Galaxy S4 deleting content off of SC card.

I really hope someone here can resolve a mystery that has been plaguing me for weeks.

A few weeks ago, I purchased a Galaxy S4 and I love the phone, except for ONE detail.

I have purchased multiple micro SD card and have tried to load it up with mp3 files and use is as a music player. I rooted it and installed Viper4Android and the sound is TREMENDOUS, however, my phone keeps deleting files off the external SD card.

I have tried this with a "generic" SD card (Class 10 64 GIG) as well as an authentic Samsung micro SD card. I have tried to do this with 2 different Galaxy S4 phones (one rooted with Hyperdrive and one stock). Doesn't seem to matter.

I thought it may have been the media scanner so I reflashed my phone with the newest version of Hyperdrive and chose not to install the media scanner and used N7Player because it contains it's own media scanner.

SAME THING! Files transfer fine to the card and show up, but are deleted later. The folders remain, but the songs are gone. It regularly loads around 30 GIG and deletes down to less than 6 GIG.

I have used a laptop and loaded the card through a card ready, through the phone, used Samsung Kies,..... Nothing works.

HELP!!

Is there some setting on the phone that controls this action?

Thanks.