The new App context manager introduced with v0.24.3 was sometimes causing an error on Windows during the cleanup actions ( GH1668). This can be changed by setting the new parameter exclude_start_string ( GH1667). mybook.to_pdf now ignores sheet names that start with a #. The app properties myapp.enable_events and myapp.interactive are now supported ( GH254). properties ( display_alerts = False ): # Alerts are disabled until you leave the with block again Import xlwings as xw app = App () with app.