Hi YoungJin, I suspect phenix.refine decided your mtz file contains anomalous data when you actually have non-anomalous data. Could you look in the phenix.refine output for something like this: ================================== X-ray data ================================= F-obs: 1yjp.mtz:FOBS_X,SIGFOBS_X R-free flags: 1yjp.mtz:R-free-flags Miller array info: 1yjp.mtz:FOBS_X,SIGFOBS_X Observation type: xray.amplitude Type of data: double, size=495 Type of sigmas: double, size=495 Number of Miller indices: 495 Anomalous flag: False ^^^^^ in particular here If you see "Anomalous flag: True" try adding this to the phenix.refine command line: xray_data.force_anomalous_flag_to_be_equal_to=False Let me know if this doesn't help. If it does help, I'd be interested to know how the .mtz file was generated. Ralf