FTS = Full-text search. It's a table only used for the collection search. Error probably means that the rowid it's trying to insert into songs_fts already exists, which is very strange, unless you have manually modified the database. Try re-creating the songs_fts data, with the following commands: Remove all songs_fts data: delete from songs_fts; Re-create songs_fts data from songs: INSERT INTO songs_fts (ROWID, ftstitle, ftsalbum, ftsartist, ftsalbumartist, ftscomposer, ftsperformer, ftsgrouping, ftsgenre, ftscomment) SELECT ROWID, title, album, artist, albumartist, composer, performer, grouping, genre, comment FROM songs;

@MarieSophieSG Check that strawberry-tagreader is running with ps -xua | grep strawberry

@Timpie Playlist / Add folder will only add the songs to the playlist (database), not the collection library, you need to add them via settings / collection, then re-add them to the playlist.