diff --git a/src/calibre/library/save_to_disk.py b/src/calibre/library/save_to_disk.py
index 845ec0590d..e94d3b35d3 100644
--- a/src/calibre/library/save_to_disk.py
+++ b/src/calibre/library/save_to_disk.py
@@ -125,6 +125,8 @@ def get_components(template, mi, id, timefmt='%b %Y', length=250,
         format_args['series'] = mi.series
         if mi.series_index is not None:
             format_args['series_index'] = mi.format_series_index()
+    else:
+        template = re.sub(r'\{series_index[^}]*?\}', '', template)
     if mi.rating is not None:
         format_args['rating'] = mi.format_rating()
     if mi.isbn: