Dear all, I am a relative newcomer to Phenix. I have a large multimeric protein structure docked into an electron density map, and I would like to further refine it by rigid-body refinement using Phenix. Is this a realistic strategy? I have made some attempts, first by converting the .mrc map file to .mtz as outlined here: https://www.phenix-online.org/documentation/reference/map_to_structure_facto... https://www.phenix-online.org/documentation/reference/map_to_structure_facto... Then I tried to refine using rigid body refinement in Phenix. However, the program quits but doesn’t really tell me why. Here’s the last part of the log file: Number of unique models: 24 Time building chain proxies: 36.85, per 1000 atoms: 0.26 Number of scatterers: 142296 At special positions: 0 Unit cell: (342, 342, 342, 90, 90, 90) Space group: P 1 (No. 1) Number of sites at special positions: 0 Number of scattering types: 4 Type Number sf(0) S 264 16.00 O 27720 8.00 N 25872 7.00 C 88440 6.00 sf(0) = scattering factor at diffraction angle 0. Writing MTZ file: /Users/xxx/Documents/Phenix/TEST/Refine_1/Test_refine_data.mtz Sorry Can anyone give me any ideas as to what went wrong? Also, is there a better way to do this? Thanks very much in advance!! A.M.