Hi Shahriar Keshvari , you'd ideally need to place the entire path to 'lmp' executable for this to run unless of course you have defined 'lmp' as an alias to the path to your executable.

This is just because you have not compiled software with the given package, you can do that by writing a bash script for including packages, and run it in the lammps folder that will activate them and then compile it with make

link for including packages: https://docs.lammps.org/Build_package.html

link for list of packages: https://docs.lammps.org/Packages_details.html

Thanks. I ended up reinstalling Lammps. I don't know what caused the issue because Lammps was working fine and suddenly stopped after I installed Spyder from Anoconda.