When I try to minimize a molecule with a linear arrangement of three or more atoms, CS MOPAC terminates with the following message: "Error from MOPAC: Fault in connectivity in data set."

When I try to minimize a molecule with a linear arrangement of three or more atoms, CS MOPAC terminates with the following message: "Error from MOPAC: Fault in connectivity in data set."

Turn off "Rectify" in the build settings and displace one of the atom slightly. Use the XYZ keyword (see MOPAC manual in Manuals folder on cd-rom for details). Then run the Mopac minimization as normal.