For the developer: the registration screen becomes un-accessible if the user changes to a different window (at least in Win 10 HP x64 with latest patches.) Moving to a different window is needed to copy the registration codes that were sent by email. Once the registration window is lost, the application locks. I resolved that by uninstalling and then reinstalling, but before registration I positioned multiple windows in different areas of the screen so I could move to the email area without hiding the registration window. Hope this info is clear and useful. Thank you, and SharewareOnSale for making this interesting software available for our use!