diff --git a/FreeSimpleGUI/window.py b/FreeSimpleGUI/window.py
index f8402df3..b6039461 100644
--- a/FreeSimpleGUI/window.py
+++ b/FreeSimpleGUI/window.py
@@ -1087,7 +1087,7 @@ def _read(self, timeout=None, timeout_key=TIMEOUT_KEY):
                 Window._root_running_mainloop.mainloop()
             except:
                 print('**** EXITING ****')
-                exit(-1)
+                sys.exit(-1)
             # print('Out main')
             self.CurrentlyRunningMainloop = False
             # if self.LastButtonClicked != TIMEOUT_KEY: