This is in F432 in a=b=c=340A at 2.85A resolution. Mac OSX 10.5.8, the machine has 8Gb memory of which something like 6Gb is hanging around begging to be used. 1,327,104,000 if that's in bytes doesn't seem all that excessive. On the other hand, 340*340*340= 39,419,600 so it's perhaps a little greedy. Limits set by shell: phil% limit cputime unlimited filesize unlimited datasize unlimited stacksize 65532 kbytes coredumpsize 0 kbytes memoryuse unlimited descriptors 256 memorylocked unlimited maxproc 266 phenix.refine does the same thing right at the end, which is kind of a shame since it takes quite a long time to run. phenix.maps does the same thing even if I ask it just to generate F,phase in MTZ format. [snip] Compute maps. Python(632) malloc: *** mmap(size=1327104000) failed (error code=12) *** error: can't allocate region *** set a breakpoint in malloc_error_break to debug show_stack(1): /usr/local/phenix-1.8-1069/cctbx_project/cctbx/miller/__init__.py(3067) double_step_filtration show_stack(2): /usr/local/phenix-1.8-1069/cctbx_project/mmtbx/maps/__init__.py(416) map_coefficients_from_fmodel show_stack(3): /usr/local/phenix-1.8-1069/cctbx_project/mmtbx/maps/__init__.py(543) __init__ show_stack(4): /usr/local/phenix-1.8-1069/build/mac-intel-osx/../../cctbx_project/mmtbx/command_line/maps.py(325) run show_stack(5): /usr/local/phenix-1.8-1069/build/mac-intel-osx/../../cctbx_project/mmtbx/command_line/maps.py(402) <module> Bus error (Python call stack above) This crash may be due to a problem in any imported Python module, including modules which are not part of the cctbx project. To disable the traps leading to this message, define these environment variables (e.g. assign the value 1): BOOST_ADAPTBX_FPE_DEFAULT BOOST_ADAPTBX_SIGNALS_DEFAULT This will NOT solve the problem, just mask it, but may allow you to proceed in case it is not critical.