Sony NWZ-A826 Operation Manual page 117

For songs
(On Windows Explorer)
Drag and drop files or folders into the "i\lUSIC" folder.
However, beyond the 8th level, neither files nor folders will be
recognized.
(On the player)
Folders are displayed in the folder name order first, then files
are displayed in the file name order. In this case, upper or
lower case letters are not distinguished.
1st
7th
8th
9th
Continued ~