Hi Haider, I would suggest, if you are not already doing that, to build and install mpich yourself in your home (which hopefully resides on a network file system mounted on all the machines of the cluster). Please use the latest stable tarball distribution (you can find it at: https://www.mpich.org/downloads/). In the README you can find instructions on how to configure and build the library. Don’t forget to add your installation path to the PATH environment or else you will still be running with the system installation instead of your local one. Best, Giuseppe On Dec 5, 2018, at 11:47 PM, Haider Abbas via discuss <[email protected]<mailto:[email protected]>> wrote: Dear Giuseppe, You are right, node 4 and node 6 are not working properly. when I am running pw.x on these node, it gives ./pw.x -i relax2.in<http://relax2.in/> >out.out & [1] 8475 mpiuser@node4:~/qe-29-11/bin$ ./pw.x: symbol lookup error: ./pw.x: undefined symbol: mpi_initialized_ I have reinstalled gfortran and mpich but still facing the same problem. Could you please further guide me how to overcome this problem. regards Haider Abbas On Wed, Dec 5, 2018 at 9:17 PM Congiu, Giuseppe via discuss <[email protected]<mailto:[email protected]>> wrote: Hello Haider, Are you compiling mpich and installing it in a global path accessible to all machines or you are using local installations? The missing symbol is a fortran symbol. The fact it is not there can mean mpich was not compiled with fortran support while your application is a fortran code. The fact that it works for a certain number of processes might mean some machine do have fortran support while other machines don’t. Can you provide some additional information about your cluster configuration? The MPICH version you are running and how you are configuring it? --Giuseppe On Dec 5, 2018, at 1:53 AM, Haider Abbas via discuss <[email protected]<mailto:[email protected]>> wrote: mpi_initialized_ _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss