Marantz saying USB device is Empty

[ShiWarrior]

Been playing my music from my USB stick with no problems

today its says "empty" but when i connect it to my PC, it says its full

I did take it out the other day to copy the files onto my PC though

but i just went to play some music, and it wont on my marantz

looks like my files have changed somehow

 

[ShiWarrior]

unfortunately didn't work

at least we tried

Thanks for the help