diff --git a/src/xcb/window.c b/src/xcb/window.c
index 60845fe..8900c3c 100644
--- a/src/xcb/window.c
+++ b/src/xcb/window.c
@@ -43,7 +43,8 @@ void get_window_class_instance(xcb_window_t window,
   xcb_icccm_get_wm_class_reply_t prop;
   const char *class = NULL;
   const char *instance = NULL;
-  if (xcb_icccm_get_wm_class_reply(conn, cookie, &prop, NULL)) {
+  bool has_reply = xcb_icccm_get_wm_class_reply(conn, cookie, &prop, NULL);
+  if (has_reply) {
     class = prop.class_name;
     instance = prop.instance_name;
   } else {
@@ -54,7 +55,7 @@ void get_window_class_instance(xcb_window_t window,
   strncpy(class_instance->class, class, LENGTH(class_instance->class));
   strncpy(class_instance->instance, instance, LENGTH(class_instance->instance));
 
-  xcb_icccm_get_wm_class_reply_wipe(&prop);
+  if (has_reply) xcb_icccm_get_wm_class_reply_wipe(&prop);
 }
 
 static visual_t *find_alpha_visual() {