Serato DJ has detected a problematic file. It is possible this file may not play correctly, and/or make your library unstable. If possible, re-encode the MP3 or remove from the library.
SEE PROBLEM FILES FOR MORE INFORMATION

The track cannot be found and will appear yellow in the library. Most likely the file has been renamed or moved location since it was first used in Serato DJ Lite.
SEE RELOCATE LOST FILES FOR MORE INFORMATION

The track has been imported from the iTunes library.
SEE SHOWING YOUR ITUNES LIBRARY

The track is locked.
SEE LOCK TRACKS FOR MORE INFORMATION

The track’s BPM and Beatgrid is locked.
SEE LOCK BPM FOR MORE INFORMATION

These tracks can be used for Karaoke.
NOTE: To use mp3+G files requires a Serato Video license
SEE KARAOKE FOR MORE INFORMATION

These tracks can be used for Karaoke, however they have been imported from iTunes.
NOTE: To use mp3+G files requires a Serato Video license.

The track is a video file. 
SEE SERATO VIDEO FOR MORE INFORMATION

The track has a Prepared Stem associated with it, and has been moved to the Stems crate. 
SEE PREPARING TRACKS FOR USE WITH STEMS FOR MORE INFORMATION

File Status and File Type Columns

Serato DJ 4.0 boasts the new File Type and File Status columns. File Status columns identify what kind of file each track is, such as audio, video, helping users quickly identify the type of content in their library. 

The File Status column shows icons that indicate the current condition or special state of a file, such as missing Problem file, read-only, beatgrid locked, or in-progress analysis, allowing users to easily spot files that may need attention or have specific restrictions.