Hi, I’m having an issue debugging an MPI program with lldb on OSX Mavericks. I get the exact behavior as described in http://lists.mpich.org/pipermail/discuss/2014-January/002074.html except using lldb instead of gdb as the debugger. I have checked that I am using the bash terminal and unfortunately am still getting the same error. Details of my installation are as follows: I have installed the mpich-clang macport (mpich-clang-fortran is active), but when I run the cpi example with mpiexec -np 1 xterm -e lldb ./cpi I get the xterm window to spawn but: Current executable set to './cpi' (x86_64). (lldb) r Process 56694 launched: './cpi' (x86_64) [cli_0]: write_line error; fd=6 buf=:cmd=init pmi_version=1 pmi_subversion=1 : system msg for write_line failure : Bad file descriptor [cli_0]: Unable to write to PMI_fd [cli_0]: write_line error; fd=6 buf=:cmd=get_appnum : system msg for write_line failure : Bad file descriptor Fatal error in MPI_Init: Other MPI error, error stack: MPIR_Init_thread(467): MPID_Init(140).......: channel initialization failed MPID_Init(422).......: PMI_Get_appnum returned -1 Process 56694 exited with status = 1 (0x00000001) (lldb) The lldb version is: lldb --version lldb-310.2.36 Any help is appreciated. Martin