diff --git a/src/calibre/utils/ipc/worker.py b/src/calibre/utils/ipc/worker.py
index e94095eac2..6614eab1ca 100644
--- a/src/calibre/utils/ipc/worker.py
+++ b/src/calibre/utils/ipc/worker.py
@@ -49,9 +49,6 @@ PARALLEL_FUNCS = {
       'read_metadata' :
       ('calibre.ebooks.metadata.worker', 'read_metadata_', 'notification'),
 
-      'save_book' :
-      ('calibre.library.save_to_disk', 'update_serialized_metadata', 'notification'),
-
       'arbitrary' :
       ('calibre.utils.ipc.worker', 'arbitrary', None),