diff --git a/racket-webview-qt.rkt b/racket-webview-qt.rkt
index 7d6d2eb..4c43b23 100644
--- a/racket-webview-qt.rkt
+++ b/racket-webview-qt.rkt
@@ -824,24 +824,28 @@
           #t)))
 
 
+(define finalizer-executed #f)
+
 (define (rkt-webview-finalizer rkt-wv-store close-windows message)
-  (dbg-webview "rkt-webview-finalizer active")
-  (when close-windows
-    (let ((open-windows (hash->list rkt-wv-store)))
-      (for-each (λ (kv)
-                  (let ((win (car kv))
-                        (handle (cdr kv)))
-                    (rkt-webview-close handle)))
-                open-windows)))
-  (rkt_webview_register_evt_callback #f)
-  (dbg-webview "Sending guard-stop message to event callback")
-  (event-callback evt-guard-stop)
-  (dbg-webview "Cleaning up FFI library")
-  (rkt_webview_cleanup)
-  (unless (eq? message #f) (error message))
-  (dbg-webview "Stopping event processing thread (kill-thread)")
-  (stop-event-processing)
-  (dbg-webview "Finalizer done")
+  (unless finalizer-executed 
+    (dbg-webview "rkt-webview-finalizer active")
+    (when close-windows
+      (let ((open-windows (hash->list rkt-wv-store)))
+        (for-each (λ (kv)
+                    (let ((win (car kv))
+                          (handle (cdr kv)))
+                      (rkt-webview-close handle)))
+                  open-windows)))
+    (dbg-webview "Sending guard-stop message to event callback")
+    (event-callback evt-guard-stop)
+    (dbg-webview "Cleaning up FFI library")
+    (rkt_webview_cleanup)
+    (unless (eq? message #f) (error message))
+    (dbg-webview "Stopping event processing thread (kill-thread)")
+    (stop-event-processing)
+    (dbg-webview "Finalizer done")
+    (set finalizer-executed #t)
+    )
   )
 
 (define (rkt-webview-exit . args)
@@ -853,7 +857,8 @@
         )
     (rkt-webview-finalizer rkt-wv-store cl-w msg)
     (unregister-custodian-shutdown rkt-wv-store custodian-finalizer)
-    ))
+    )
+  )
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Cleanup on exit