ChemDraw Chem3D: How do I open a file saved using the Chem3D file format in MacroModel

The Chem3D file format available in MacroModel saves files based on the Chem3D version 2.0 atom type definition protocol. In order for these files to be opened and interpreted correctly in Chem3D version 3.0 or later, you should use the Cartesian Coordinates-2 file interpreter. 

NOTE: In Chem3D version 3.1 or later, you can use the MacroModel file format to open files saved in the native MacroModel file format.