Removing gold locks from music library in Aerator DJ

Without knowing more I would guess these are DRM protected tracks in your library that Aerator can see, but knows it cannot play. Look in the Music app, Songs view, and see what is given as the Kind for these tracks.

tt2

Ah, in which case see Repair security permissions for iTunes/Music for Mac - Apple Community. Perhaps that is the issue. That said it would probably be better to change metadata in Music rather than a third party app.

tt2

Serato – Lock Tracks

"If a track displays a gold lock in the Status column, then the file information for the track itself cannot be changed. You will not be able to change any of the track’s information permanently in Serato DJ Pro."