diff --git a/submodule.c b/submodule.c
index 5865795b9f7c47..fa21c7bb72436c 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1052,11 +1052,12 @@ unsigned is_submodule_modified(const char *path, int ignore_untracked)
 	git_dir = read_gitfile(buf.buf);
 	if (!git_dir)
 		git_dir = buf.buf;
-	if (!is_directory(git_dir)) {
+	if (!is_git_directory(git_dir)) {
+		if (is_directory(git_dir))
+			die(_("'%s' not recognized as a git repository"), git_dir);
 		strbuf_release(&buf);
 		/* The submodule is not checked out, so it is not modified */
 		return 0;
-
 	}
 	strbuf_reset(&buf);