I have just upgraded my Kubuntu from 18.04 to 20.04. Unfortunately there is an error that keeps showing up everytime I use apt upgrade or installing something with apt. The error is:

update-alternatives: error: /var/lib/dpkg/alternatives/mpi corrupt: slave link same as main link /usr/bin/mpicc

It has been reported and yet has not been patched until the time I write this question.

After more than a month trying various ways to deal with this problem I finally found the solution as you can see below. I hope it is useful for you who met with the same problem.

First remove the update-alternatives for openmpi:

sudo rm -f /etc/alternatives/mpi* /var/lib/dpkg/alternatives/mpi*

Then install openmpi-bin again:

sudo apt install open-mpi

answer Y when asked for confirmation.

In Ubuntu 22.04 (or if the above line doesn't work) - try this instead:

sudo apt install openmpi-bin