diff --git a/core/Migrations/Version13000Date20170718121200.php b/core/Migrations/Version13000Date20170718121200.php
index 819eb84f11845..fff993f75548f 100644
--- a/core/Migrations/Version13000Date20170718121200.php
+++ b/core/Migrations/Version13000Date20170718121200.php
@@ -730,6 +730,8 @@ public function changeSchema(IOutput $output, \Closure $schemaClosure, array $op
 			$table->setPrimaryKey(['objecttype', 'objectid', 'systemtagid'], 'som_pk');
 			//			$table->addUniqueIndex(['objecttype', 'objectid', 'systemtagid'], 'mapping');
 			$table->addIndex(['systemtagid', 'objecttype'], 'systag_by_tagid');
+			// systag_by_objectid was added later and might be missing in older deployments
+			$table->addIndex(['objectid'], 'systag_by_objectid');
 		}
 
 		if (!$schema->hasTable('systemtag_group')) {