diff --git a/builtin/add.c b/builtin/add.c
index ea762a41e3..afccf2fd55 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -141,6 +141,8 @@ static int renormalize_tracked_files(const struct pathspec *pathspec, int flags)
 {
 	int i, retval = 0;
 
+	/* TODO: audit for interaction with sparse-index. */
+	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr; i++) {
 		struct cache_entry *ce = active_cache[i];