CRM Outlook Client Error - There was an error while executing action for thie menu/button error followed by a blank activity screen in Outlook

Whilst working on a clients machine, i stumbled across the above.....shortly followed with the below when i tried to create a new appointment from the CRM toolbar.

However, this only was happening on certain machines.

Later on i discovered that the machines that still had UAC switched on where the machines that showing this error. Switching off the setting in the control panel solves the problem.

Jonathan