diff --git a/kitty/state.c b/kitty/state.c
index 697a52115..59c10e969 100644
--- a/kitty/state.c
+++ b/kitty/state.c
@@ -421,6 +421,7 @@ PYWRAP1(set_boss) {
 
 PYWRAP0(destroy_global_data) {
     Py_CLEAR(global_state.boss);
+    free(global_state.os_windows); global_state.os_windows = NULL;
     Py_RETURN_NONE;
 }