Hi Archie
No still did not work; have solved it though, I migrated the project to VS 2015 on Windows 10 and built it there and works. So I thing my install of VS2012 has issues with the .net framework 4 on Windows 8.1. Both are 64bit operating systems. The only other projects I maintain on VS2012 are version 3.5 framework and have been migrating them gradually but struck some issues going to the latest framework on Windows 7 clients.
All good have the AHMI project working exactly how I want it running on a Modbus driver to Automation Direct Productivity 3000.
Thanks for your help
Regards Dale