diff --git a/src/newconf.c b/src/newconf.c
index 82fd44850..2cb8824d4 100644
--- a/src/newconf.c
+++ b/src/newconf.c
@@ -1593,6 +1593,7 @@ conf_set_general_default_umodes(void *data)
 		/* don't allow +o */
 		case 'o':
 		case 'S':
+		case 'Z':
 		case ' ':
 			break;