diff --git a/indexes.yaml b/indexes.yaml
index 38f21a03..526228bf 100644
--- a/indexes.yaml
+++ b/indexes.yaml
@@ -489,14 +489,6 @@ indexes:
           key:
               _id: hashed
 
-    - collection: attachments.files
-      type: gridfs # index applies to gridfs database
-      index:
-          name: related_attachments
-          key:
-              metadata.c: 1
-              metadata.m: 1
-
     - collection: attachments.files
       type: gridfs # index applies to gridfs database
       index: