Hi, I am having a weird problem with mdrun_mpi. My command was: mdrun_mpi -s 3.tpr -o 3.trr -c 7.gro -e mdo1.edr But instead of creating a 7.gro as an output file, the program generated a .pdb file output for every step!!! I have never seen such behaviour with mdrun before. Any insights?? Madhuri Agashe