Dear phenix experts: I have a data in R32 at 2.3A. 4 molecules/A.U. I got the following error message when I run refinement wiht phenix v1.5-2: =============================== refinement start ============================== Traceback (most recent call last): File "/usr/local/phenix-1.5-2/phenix/phenix/command_line/refine.py", line 11, in <module> command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/usr/local/phenix-1.5-2/phenix/phenix/refinement/command_line.py", line 89, in run call_back_handler=call_back_handler) File "/usr/local/phenix-1.5-2/phenix/phenix/refinement/driver.py", line 1121, in run call_back_handler = call_back_handler) File "/usr/local/phenix-1.5-2/phenix/phenix/refinement/strategies.py", line 185, in refinement_machine log = log) File "/usr/local/phenix-1.5-2/cctbx_project/mmtbx/utils.py", line 1371, in fmodel_manager max_number_of_bins = max_number_of_resolution_bins) File "/usr/local/phenix-1.5-2/cctbx_project/mmtbx/f_model.py", line 358, in __init__ mask_params = self.mask_params) File "/usr/local/phenix-1.5-2/cctbx_project/mmtbx/masks.py", line 175, in __init__ self.compute_f_mask(twin = twin) File "/usr/local/phenix-1.5-2/cctbx_project/mmtbx/masks.py", line 264, in compute_f_mask asu_mask.compute(sites_frac, atom_radii) RuntimeError: mmtbx Error: the mask grid size: 576 * 576 * 270 = 89579520 is too big maximum allowed size is 67108863 64 bit OS and software might be required for such a big mask. How can I tackle this problem? Any suggestion is highly appreciated. Xue