Tracks in iTunes are shown, but they cannot be played. [Serato DJ]

QuickTime of Apple is needed to play the music files in AAC format.

　Please install QuickTime into your computer.

　After installing QuickTime, launch Serato DJ and untick "Show iTunes Library" in Library + Display on SETUP window in Serato DJ.

　Then, tick it again to start using these files.

　Please ensure iTunes is updated to the latest version.

Also, please see the FAQ in the Serato website from this link.

iTunes and QuickTime are trademarks of Apple Inc., registered in the U.S. and other countries.