The error "Attempting to use an MPI routine before initializing MPICH" in our application that uses builds master r8599. In the link below, at the end it was mentioned that the issue was resolved in V5. https://bitbucket.org/fathomteam/moab/issues/24/parallelcomm-double-free-or-... We did not get any such error in the older builds, for example r6854 . Madhu