Hi, I'm having a strange problem with mpich. I built & installed it on machine A (a Lenovo T61 running OpenSuSE 13.1), and it seems to run fine on that machine (using mpiexec to start multiple processes). Now I built it on machines B & C (both Intel quad-core, one with OpenSuSE 12.2, one with 13.1). The code is from the same .tgz file ( mpich-3.1.2.tgz) and configured the same (--prefix=/opt/mpich --disable-fortran), but 'make testing' fails with messages like the following. (But if I make e.g. the cpi example and run it as a non-MPI program, it runs ok.) As far as I can tell, the relevant paths & environment vars are exactly the same on all three systems. Any clues as to what my problem could be, or even where to start looking? I did try running mpiexec with the -verbose flag, but none of the output seemed to make sense to me. James Unexpected output in collparmt: Fatal error in MPI_Init: Other MPI error, error stack: Unexpected output in collparmt: MPIR_Init_thread(498)..............: Unexpected output in collparmt: MPID_Init(177).....................: channel initialization failed Unexpected output in collparmt: MPIDI_CH3_Init(89).................: Unexpected output in collparmt: MPID_nem_init(320).................: Unexpected output in collparmt: MPID_nem_tcp_init(171).............: Unexpected output in collparmt: MPID_nem_tcp_get_business_card(418): Unexpected output in collparmt: MPID_nem_tcp_init(377).............: gethostbyname failed, q2 (errno 1) Unexpected output in collparmt: Unexpected output in collparmt: =================================================================================== Unexpected output in collparmt: = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES Unexpected output in collparmt: = PID 29078 RUNNING AT q2 Unexpected output in collparmt: = EXIT CODE: 1 Unexpected output in collparmt: = CLEANING UP REMAINING PROCESSES Unexpected output in collparmt: = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES