Hi All What might cause this action to fail, pH=7.4, H added to protein before adding charge? No errors were thrown. Both DOCK-Prep, and adding H then charge both do not change the PDB file (no charges added to respective atoms). Log reports "Using Amber 20 recommended default charges and atom types for standard residues" Alternative command 'addcharge standardizeResidues 5BU,CSL,MSE,UMS' reports "Using Amber 20 recommended default charges and atom types for standard residues" and no errors but don't add charges to saved PDB file. Charges are added with another structure editor. Thanks for insights! **CONFIDENTIALITY NOTICE** This e-mail communication and any attachments are for the sole use of the intended recipient and may contain information that is confidential and privileged under state and federal privacy laws. If you received this e-mail in error, be aware that any unauthorized use, disclosure, copying, or distribution is strictly prohibited. If you received this e-mail in error, please contact the sender immediately and destroy/delete all copies of this message.