1 files changed, 2 insertions, 0 deletions
diff --git a/mbox.c b/mbox.c
index 0f07cc49..254db452 100644
--- a/mbox.c
+++ b/mbox.c
@@ -1406,6 +1406,7 @@ struct mx_ops mx_mbox_ops = {
   .check = mbox_check_mailbox,
   .sync = mbox_sync_mailbox,
   .msg_padding_size = mbox_msg_padding_size,
+  .save_to_header_cache = NULL,
 };
 
 struct mx_ops mx_mmdf_ops = {
@@ -1419,4 +1420,5 @@ struct mx_ops mx_mmdf_ops = {
   .check = mbox_check_mailbox,
   .sync = mbox_sync_mailbox,
   .msg_padding_size = mmdf_msg_padding_size,
+  .save_to_header_cache = NULL,
 };