I am trying boost::mpi on a big code & getting the following error message from mac mpiC++ (same from an intel super-computer). Can anyone pick out something quickly from that to help please or do you need to see more? I'd like to figure out what I did to not do it! :) Thanks! Jacques Process=1's mpe_decomp1d MiniGridSize= 3 3 3 Pause @ "main: 879: Domain decomposition" if 1 process: <Enter> or <Return> continues; ^C aborts: init_internal_neighbors_wf: Process 1 of 2 exchanging (if necessary) w/+/-1! Sender=1, Receiver=0 [jacques-richards-mac-mini:00474] *** Process received signal *** [jacques-richards-mac-mini:00474] Signal: Segmentation fault (11) [jacques-richards-mac-mini:00474] Signal code: Address not mapped (1) [jacques-richards-mac-mini:00474] Failing at address: 0x200000001 [jacques-richards-mac-mini:00474] [ 0] 2 libSystem.B.dylib 0x00007fff86fa51ba _sigtramp + 26 [jacques-richards-mac-mini:00474] [ 1] 3 ??? 0x0000000000000000 0x0 + 0 [jacques-richards-mac-mini:00474] [ 2] 4 Mg 0x000000010010ff0e _ZN5boost3mpi6detail24ignore_skeleton_oarchiveINS1_16content_oarchiveEE13save_overrideIP12lattice_typeEEvRKT_i + 40 [jacques-richards-mac-mini:00474] [ 3] 5 Mg 0x000000010010ff3a _ZN5boost7archive6detail18interface_oarchiveINS_3mpi6detail16content_oarchiveEElsIKP12lattice_typeEERS5_RT_ + 42 [jacques-richards-mac-mini:00474] [ 4] 6 Mg 0x000000010010ff6e _ZNK5boost13serialization3nvpIKP12lattice_typeE4saveINS_3mpi6detail16content_oarchiveEEEvRT_j + 40 [jacques-richards-mac-mini:00474] [ 5] 7 Mg 0x000000010010ff93 _ZN5boost13serialization6access1 ... .. .