Greetings all!

Is there a general workflow for preparing dwg's for inventor?

The problem:
Customers send me files from AutoCAD. Generally the dwg's come into inventor fine using the New Layout from DWG. The problem is when I make a new sub layout I get a warning stating that the graphics from linked DWG overlay will not be added to the sub-layout and I get no dwg graphics in the new sub-layout. The interesting thing in this one instance, there is only one dwg file no overlay files. I run into similar problems all the time with customer cad files (missing ref files). I would just like to know if there is a workflow that inventor people use to prep the DWG's before importing.