diff --git a/ui/vnc.c b/ui/vnc.c
index cf9b597d1d..6854fdb02f 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1257,7 +1257,7 @@ ssize_t vnc_client_io_error(VncState *vs, ssize_t ret, Error **errp)
         if (ret == 0) {
             VNC_DEBUG("Closing down client sock: EOF\n");
         } else if (ret != QIO_CHANNEL_ERR_BLOCK) {
-            VNC_DEBUG("Closing down client sock: ret %d (%s)\n",
+            VNC_DEBUG("Closing down client sock: ret %zd (%s)\n",
                       ret, errp ? error_get_pretty(*errp) : "Unknown");
         }