The new macOS Catalina is not compatible with DJ Software
If you are a DJ using Rekordbox, do not upgrade yet!
Apple’s new macOS Catalina update is a major issue for DJs who use Rekordbox as this new music app which replaces iTunes does not have XML file support and that summed up means it is impossible to export the iTunes library.
This new music app overall looks really nice for general users but Apple’s advice states “if you rely on DJ software that needs this XML file to function, do not update to Catalina until individual developers have issued compatibility updates for the new operating system.”