diff --git a/src/musiksammlung/organizer.py b/src/musiksammlung/organizer.py
index f220498..4d8a572 100644
--- a/src/musiksammlung/organizer.py
+++ b/src/musiksammlung/organizer.py
@@ -131,8 +131,12 @@ def build_mapping(
 
         for audio_file, track in zip(audio_files, disc.tracks):
             safe_title = sanitize_filename(track.title)
-            safe_artist = sanitize_filename(track.artist or album.artist)
-            new_name = f"{track.track_number:02d}_-_{safe_title}_-_{safe_artist}{audio_file.suffix}"
+            artist_raw = track.artist or album.artist
+            if artist_raw:
+                safe_artist = sanitize_filename(artist_raw)
+                new_name = f"{track.track_number:02d}_-_{safe_title}_-_{safe_artist}{audio_file.suffix}"
+            else:
+                new_name = f"{track.track_number:02d}_-_{safe_title}{audio_file.suffix}"
             mapping[audio_file] = target_dir / new_name
 
     return mapping