Hi,
Do you get this error when trying to interact with the main window itself or with controls located in it (such as buttons)? What happens if you call the Activate method of your main window? Are you sure that your test tries to work with the correct control (you can check this on a breakpoint or by using object snapshots)? Depending on your application, there can be invisible objects which meet the same recognition parameters, but which are not accessible. If TC actually tries to work with one of such objects, it will fail.
