Small pat of 2TB USB Disk can read by Volumio

I connected a 2 TB UDB disk and 300 GB USB Disk to Volumio. however, only a very small part of them perceived by Volumio. Totally there are more than 2500 Album in two usb disk. But Volumio can show only 416 of them.
Can anyone give me help on this topic:

It has solved.