Dear phenixBBers I have a curious case of refinement of a 2.6 Angs structure, where some of the atoms have a calculated b-factor of 0.00. It seems to be somewhat random where this occurs and includes atoms within the backbone e.g. the nitrogen in the following residue: ATOM 2014 N THR A 264 -2.685 42.357 -35.833 1.00 0.00 N ATOM 2015 CA THR A 264 -3.952 41.776 -35.425 1.00 1.50 C ATOM 2016 CB THR A 264 -4.684 41.052 -36.593 1.00 1.70 C ATOM 2017 OG1 THR A 264 -4.077 39.772 -36.846 1.00 2.24 O ATOM 2018 CG2 THR A 264 -4.669 41.867 -37.855 1.00 1.72 C ATOM 2019 C THR A 264 -3.687 40.729 -34.368 1.00 2.42 C ATOM 2020 O THR A 264 -2.571 40.210 -34.263 1.00 2.63 O The structure contains 4 NCS related monomers but with a quick glance I don't see any obvious correlation between each one as to which atoms are 0.00. I did use phenix.pdbtools to randomise the B-factors (no atoms had a value 0.00 afterwards) but upon repeating the refinement the same problem occurs. Does anyone have a suggestion how to fix this ? Cheers Stephen