Asus RT-AC58U - UPnP Media Server - doesn't see all files

Hello

I have a problem with mi UPnP Media Server on Asus RT-AC58U.
I enabled my server and I can see the drive connected through USB port to my router but when I try to access files (photos and videos) from TV or Windows Media Player on laptop I can not see all files. I can see only part of them.
I found out that when I copy some file (which can't be accessed from TV or WMP) to another folder and then copy it back to the original folder it starts to work - this file is available from TV or...

Asus RT-AC58U - UPnP Media Server - doesn't see all files