Thanks for your quick response Tanya. Although it didn't fix the problem, it did set me off in the right direction and I noticed that TC was testing as if it was a 'blackbox' app, i.e. not recognising .NET at all no matter what I did. Solution: Uninstall and reinstall TC and now it is at least recognising the forms and controls correctly. I did notice that we have quite a number of new Devexpress controls that do not appear in TC's Properties-->Object Mapping list as we are currently using ver 13.2.5 which I hope will not cause any grief.