My Book not refreshing directory contents

Hi,

Perhaps this is a common issue - but I can’t seem to figure out why this is happening…

Background: I have two WD external hard drives - one elements and one my book - they are both 8tb. When attached to the PC, both units can transfer and display files but when attached to my nvidia shield, only the elements external hard drive properly displays any new files added. The my book external hard drive only shows what was initially put on it, and not anything afterwards. Yet, I know the data is there cause I can pop it over to the PC and it shows everything.

So whats going on?