I can't open a Chem3D file created by the UNIX version of MacroModel. I get an error message stating, "Sorry, the Open...command cannot be completed because the file "yourfile.c3d" was saved in a format unrecognized by this version of CS Chem3D or is not in the expected format."
First, please note that there are two programs called "MacroModel". The UNIX version is a molecular modeling program. The PC version is graphics software program. We can open files from the UNIX version. The file format that MacroModel for UNIX writes is not the Chem3D format, despite the *.c3d extension. Instead, MacroModel UNIX is actually writing a cartesian coordinates 2 file. If you change the *.c3d extension to *.cc2, you should be able to open the file in Chem3D.