v23 slow to become usable

Hi,
When I launch v23 by double-clicking a .dwg file there is an annoying delay of a few seconds after Bricscad starts before I can do anything like zoom or start drawing; even the pointer disappears when I move it over the window.
What is the program doing during this time, and can I alter a setting to change the behaviour? v22 did not do this.
Thanks
Jamie