Thanks for your help, it does indeed seem as if Laminar had enabled it, as i just recieved a message when logging into the sim stating they have removed the auto selection of Zinc.
All working fine again.
Many thanks
There’s a checkbox on the right hand side of the Graphics settings in X-Plane. It may have been automatically enabled, if so, I can only apologise on Laminar’s behalf as I believe this is a premature decision.