Overlapping geometry in Contact Regions
 

Hi everybody
I'm a newbie in CFD simulation. I am using ANSYS Fluent 16.0 to model a 3D solid geometry with fluid enclosure. When I generate and after uptdate the mesh, ANSYS return to me this error message:
"The mesh file exporter does not support overlapping geometry in Contact Regions. Please resolve the issue and try again."
I try to fix it reading user's guide that suggests me to click with right mouse's bottun on command "mesh" and follow path "Show> Geometry in Overlapping Named Selections". But, when I do it, I don't find the command "Geometry in Overlapping Named Selections". Why?
Someone help me please?
Any help would be greatly appreciated. :)
Thank You