Certain formatted checkpoint files that are read into Chem3D Pro do not display the molecular orbitals. Some molecules seem to optimize and display their results with no problem, while others give the error message:
"Sorry, the access code is invalid"
The program succeeds in reading in the geometry and the orbital energies, but when one is to be plotted, I get the same error message.
The field used to identify these molcules in the checkpoint file (the first line) is also used in cube files. When Chem3D tries to parse the cube files produced for the orbitals etc., it thinks that the name of the molecule is a type density. You will need to rename the molecule to correct the problem. For example, rename a molecule from "135 TBB" to "TBB135".