diff --git a/editor.py b/editor.py
index a6c6323..4fdd795 100644
--- a/editor.py
+++ b/editor.py
@@ -165,7 +165,74 @@ def write_metadata(path, metadata):
         raise ValueError("Speichern der ID3-Tags hat zu lange gedauert")
     except OSError as exc:
         temp.unlink(missing_ok=True)
-        raise ValueError(f"ID3-Tags konnten nicht gespeichert werden: {exc}")
+        raise ValueError(f"Speichern der ID3-Tags fehlgeschlagen: {exc}")
+
+
+def update_finished_file(old_filename, new_filename, metadata):
+    """Update metadata and optionally rename a finished file in one operation."""
+    old_path = finished_path(old_filename)
+    new_filename = clean_new_filename(new_filename)
+    if old_path is None or not old_path.is_file():
+        raise ValueError("Datei nicht gefunden")
+    if new_filename is None:
+        raise ValueError("Ungültiger Dateiname")
+
+    new_path = FINISHED_DIR / new_filename
+    if new_path != old_path and new_path.exists():
+        raise ValueError("Eine Datei mit diesem Namen existiert bereits")
+
+    date = str(metadata.get("date", "")).strip()
+    if not date:
+        raise ValueError("Zeitpunkt fehlt")
+    try:
+        dt = datetime.fromisoformat(date)
+        if dt.tzinfo is None:
+            dt = dt.replace(tzinfo=ZoneInfo("Europe/Berlin"))
+        date = dt.isoformat()
+    except ValueError:
+        raise ValueError("Ungültiger Zeitpunkt")
+
+    values = {
+        "date": date,
+        "artist": str(metadata.get("artist", "")).strip(),
+        "title": str(metadata.get("title", "")).strip(),
+        "album": str(metadata.get("album", "")).strip(),
+    }
+
+    # Build the complete new MP3 first. The original remains untouched until
+    # FFmpeg has successfully written the new file.
+    temp = FINISHED_DIR / f".{new_path.name}.update.tmp.mp3"
+    temp.unlink(missing_ok=True)
+    cmd = [
+        "ffmpeg", "-hide_banner", "-loglevel", "error", "-y",
+        "-i", str(old_path),
+        "-map", "0",
+        "-c", "copy",
+        "-map_metadata", "-1",
+    ]
+    for key, value in values.items():
+        cmd += ["-metadata", f"{key}={value}"]
+    cmd.append(str(temp))
+
+    try:
+        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
+        if result.returncode != 0 or not temp.is_file() or temp.stat().st_size == 0:
+            raise ValueError("ID3-Tags konnten nicht gespeichert werden")
+
+        temp.replace(new_path)
+        if new_path != old_path:
+            old_path.unlink()
+
+        return new_path
+    except subprocess.TimeoutExpired:
+        temp.unlink(missing_ok=True)
+        raise ValueError("Speichern der Datei hat zu lange gedauert")
+    except OSError as exc:
+        temp.unlink(missing_ok=True)
+        raise ValueError(f"Datei konnte nicht gespeichert werden: {exc}")
+    except ValueError:
+        temp.unlink(missing_ok=True)
+        raise
 
 
 def delete_file(kind, filename):
@@ -1013,20 +1080,15 @@ async function saveFinishedMeta() {
       album: document.getElementById('finishedAlbum').value.trim()
     };
 
-    let targetFilename = filename;
-    if (newFilename.replace(/\.mp3$/i, '') !== filename.replace(/\.mp3$/i, '')) {
-      const renameResponse = await fetch('/api/file', {
-        method: 'POST', headers: {'Content-Type':'application/json'},
-        body: JSON.stringify({action:'rename', kind:'finished', filename, new_filename:newFilename})
-      });
-      const renameResult = await renameResponse.json();
-      if (!renameResponse.ok || !renameResult.success) throw new Error(renameResult.error || `HTTP ${renameResponse.status}`);
-      targetFilename = renameResult.filename;
-    }
-
     const response = await fetch('/api/file', {
       method: 'POST', headers: {'Content-Type':'application/json'},
-      body: JSON.stringify({action:'update_metadata', kind:'finished', filename:targetFilename, metadata})
+      body: JSON.stringify({
+        action: 'update_finished',
+        kind: 'finished',
+        filename,
+        new_filename: newFilename,
+        metadata
+      })
     });
     const result = await response.json();
     if (!response.ok || !result.success) throw new Error(result.error || `HTTP ${response.status}`);
@@ -1204,6 +1266,13 @@ def api_file():
         if action == "rename":
             path = rename_file(kind, filename, data.get("new_filename"))
             return jsonify({"success": True, "filename": path.name})
+        if action == "update_finished":
+            if kind != "finished":
+                return jsonify({"success": False, "error": "Metadaten können nur bei bearbeiteten Aufnahmen geändert werden"}), 400
+            metadata = data.get("metadata") or {}
+            path = update_finished_file(filename, data.get("new_filename"), metadata)
+            return jsonify({"success": True, "filename": path.name})
+
         if action == "update_metadata":
             if kind != "finished":
                 return jsonify({"success": False, "error": "Metadaten können nur bei bearbeiteten Aufnahmen geändert werden"}), 400