Sorry I did not send the full error message... I can load mesh and geometry however it is just fluent i cant load. As fluent was workig for me before I was able to set up what i wanted and luckily I can still access the CFD post. I have external data included but it is not linked to what I am trying to solve, I was just remodelling someones geometry. I have had this external geometry in this document for months and it hasn't caused a problem. nAs for adding material not in fluent database, the fluid i am using is air & the inertial particle being used is water, these are both in the dropdown menus in fluent. n