The Relocate Lost Files button is located in the files panel. If you’ve moved the location of files which are already in your library, they will show up as not found and be displayed in red. Drag and drop a folder from Finder (Mac) or Explorer (Windows) onto the Relocate Lost Files button to search it, and any sub- folders, for files currently marked as not found in your library. Doing this will update the database with their new location.
NOTE: Clicking the Relocate Lost Files button will search through all attached drives for missing files but may take a very long time depending on size of Serato DJ library and complexity of hard drive file organisation.