Hi! I was trying to fit my ligands into my model and density. And I have successfully fitted 2 ligands (same molecule) but my 3rd ligand is different molecule. After fitting my 3rd ligand (with COOT) and merged it with my protein, II created a restraint file with: phenix.elbow my_model_coot-0..pdb --do-all --output=all_ligands It created all_ligand.cif, which I used for in my next refinement with Phenix (GUI). I supplied my density, model and the restraint file and run phenix.refine. Unfortunatate I'm getting this error message when it starts to run phenix.refine and opening COOT window: Sorry: Fatal problems interpreting PDB file: Number of atoms with unknown nonbonded energy type symbols: 1 Please edit the PDB file to resolve the problems and/or supply a CIF file with matching restraint definitions, along with apply_cif_modification and apply_cif_link parameter definitions if necessary (see phenix.refine documentation). Also note that phenix.elbow is available to create restraint definitions for unknown ligands. I have use the same procedure for fitting my first 2 ligands. and it worked. But this time it failed! What do you think I should do? Thanks Hermi