diff --git a/trytond/trytond/backend/sqlite/database.py b/trytond/trytond/backend/sqlite/database.py
index ed8dc264e7..dc4863cd55 100644
--- a/trytond/trytond/backend/sqlite/database.py
+++ b/trytond/trytond/backend/sqlite/database.py
@@ -525,7 +525,11 @@ class Database(DatabaseInterface):
         self._conn.execute('PRAGMA foreign_keys = ON')
         self._conn.execute('PRAGMA journal_mode = WAL')
         self._conn.execute('PRAGMA synchronous = NORMAL')
-        self._conn.execute('PRAGMA optimize')
+        try:
+            self._conn.execute('PRAGMA optimize')
+        except DatabaseOperationalError:
+            # database may be locked
+            pass
         return self
 
     def _make_uri(self):