diff --git a/src/window.c b/src/window.c
index cbf0ff8..de85739 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2489,6 +2489,10 @@
 
     while (firstwin != NULL)
 	(void)win_free_mem(firstwin, &dummy, NULL);
+
+    /* No window should be used after this. Set curwin to NULL to crash
+     * instead of using freed memory. */
+    curwin = NULL;
 }
 #endif