Hi, I am having troubles running mpiexec (from MPICH 3.1) on remote hosts with xterm (for debugging purposes) from an Ubuntu box. The following command works perfectly in local: mpiexec -n 1 xterm However, if I use a machine file: mpiexec -f macfile -n 1 xterm xterm Xt error: Can't open display: xterm: DISPLAY is not set =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = PID 19225 RUNNING AT thwomp.mcs.anl.gov = EXIT CODE: 1 = CLEANING UP REMAINING PROCESSES = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES =================================================================================== X forwarding is activated: fisaila@howard:bin$ grep X11Forwarding /etc/ssh/sshd_config X11Forwarding yes The following command works: fisaila@howard:bin$ ssh thwomp.mcs.anl.gov xterm Any suggestion how to solve this? Thanks Florin