# Mpi error when running ff-mpirun on Ubuntu 20.04.2 LTS

**URL:** <https://community.freefem.org/t/mpi-error-when-running-ff-mpirun-on-ubuntu-20-04-2-lts/1068>\
**Category:** FreeFEM installation\
**Created:** [June 28, 2021, 2:23pm UTC](https://community.freefem.org/t/mpi-error-when-running-ff-mpirun-on-ubuntu-20-04-2-lts/1068 "2021-06-28T14:23:33Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![yongxing](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/yongxing/32/3632_2.png) [@yongxing](https://community.freefem.org/u/yongxing)\
**Post date:** [June 28, 2021, 2:23pm UTC](https://community.freefem.org/t/mpi-error-when-running-ff-mpirun-on-ubuntu-20-04-2-lts/1068/1 "2021-06-28T14:23:33Z")

</div>

error while loading shared libraries: libmpi\_cxx.so.20: cannot open shared object file: No such file or directory

I am sure libopenmpi-dev has been install already.

Please can anyone suggest what’s wrong?

I followed the guideline for Ubuntu installation, and installed  
FreeFEM\_4.9\_Ubuntu\_withPETSc\_amd64.deb

BTW, serial FreeFem++ command works well.