Dear All, I would like to create a SA-omit map for two carbohydrate chains present in my structure. My attempts using the command phenix.autobuild data=data.mtz model=final.pdb omit_box_pdb=cho2.pdb composite_omit_type=sa_omit lead to a message in the log file saying: Failed to carry out AutoBuild_set_up_build: Sorry, unable to define an omit region with cho2.pdb res_start = None res end = None chain = '' ? Possibly no atoms? The procedure works fine with protein residues so I am assuming that phenix.autobuild is ignoring the sugars in the original pdb file (as it says in the log file..). Is this correct? How can I fix the problem? I am running Phenix 1.3b. Many thanks in advance for your help. Regards Enrico -- Enrico Girardi Randall Division of Cell and Molecular Biophysics King's College London New Hunt's House Guy's Campus London SE1 1UL Tel +44 (0)20 7848 6419 Fax +44 (0)20 7848 6435