Hi, I did 2ns simulation as an equilibration step by mdrun, Mdrun -v -deffnm md1 and now i want to do product run for 100ns by mpirun, Grompp -p -f -c md1.gro -t md1.cpt -o md2.tpr -maxwarn 1 Mpirun -np 8 mdrun -v -deffnm md2 but it will crush after few minutes at intialization... Is that because i use mpirun? Best Rose