diff --git a/src/dir.c b/src/dir.c
index 8e0d96d9..1a27c84a 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -479,7 +479,7 @@ dir_list_file(parray *files, const char *root, bool exclude, bool omit_symlink,
 	{
 		/* For external directory this is not ok */
 		if (external_dir_num > 0)
-			elog(ERROR, "External directory is not found: %s", root);
+			elog(ERROR, "External directory is not found: \"%s\"", root);
 		else
 			return;
 	}