For ISO 9660 - compliant format, the maximum allowable depth of nested folders is 8, including the root directory (folder).
When CD-R disc is used, playback is possible only for discs, which have been finalized.
Make sure that when MP3 CD-R or CD-RW is burned that it is formatted as a data disc and NOT as an audio disc.
You should not write non-MP3 files or unneeded folders along with MP3 files on the disc otherwise it takes a long time until the unit starts to play MP3 files.
With some CD-R or CD-RW media, data may not be properly written depending on their manufacturing quality. In this case, data may not be reproduced correctly. High quality CD-R or CD-RW disc is recommended.
Up to 16 characters are displayed for the name of an Album or a Track. ID3TAG version 1.x is required.
Note that the unit may not play Tracks in the order that you wrote them to the disc.