diff --git a/notes.c b/notes.c
index 1978244398..bb03eb0364 100644
--- a/notes.c
+++ b/notes.c
@@ -940,7 +940,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 		return;
 	if (get_tree_entry(object_sha1, "", sha1, &mode))
 		die("Failed to read notes tree referenced by %s (%s)",
-		    notes_ref, object_sha1);
+		    notes_ref, sha1_to_hex(object_sha1));
 
 	hashclr(root_tree.key_sha1);
 	hashcpy(root_tree.val_sha1, sha1);