This occurs when running phenix.refine_gui with twin mode turned on. A Python error was detected. This is almost certainly a bug; please send an email containing this message to [email protected] so we can fix it. Thanks! TypeError : float argument required, not NoneType Traceback: Traceback (most recent call last): File "/protos/package/strucbio/phenix-1.4-3/phenix/wxGUI2/Refine.py", line 269, in OnUpdate self.notebook.run_tab.OnStatsUpdate(event) File "/protos/package/strucbio/phenix-1.4-3/phenix/wxGUI2/RefineNotebook.py", line 277, in OnStatsUpdate self.xyzerr_val.SetLabel("%.2f" % f_info.ml_coordinate_error) TypeError: float argument required, not NoneType Mark Knapp Structural Chemistry NIBR 4560 Horton Street M/S 4.4 Emeryville, CA 94608 510-923-6926