diff --git a/src/supplicant-manager/nm-supplicant-config.c b/src/supplicant-manager/nm-supplicant-config.c
index 4fb6a1eef0..6df7168fd3 100644
--- a/src/supplicant-manager/nm-supplicant-config.c
+++ b/src/supplicant-manager/nm-supplicant-config.c
@@ -621,7 +621,7 @@ nm_supplicant_config_add_setting_wireless_security (NMSupplicantConfig *self,
 			}
 		} else {
 			/* Invalid PSK */
-			nm_warning ("Invalid PSK length %d: not between 8 and 63 characters inclusive.", psk_len);
+			nm_warning ("Invalid PSK length %u: not between 8 and 63 characters inclusive.", (guint32) psk_len);
 			return FALSE;
 		}
 	}