MPI only starts 1 process

I'm running a simulation in Sim4Life EM FDTD solver, but its not using the hardware as expected: only a very small percentage of the processor is used during the simulation, which ends up with a very large estimated time to complete.

Task bar:

System Usage during simulation:

The solver is set to automatically design the number of cores for the simulation. An error is given if I try to set it manually:

I'm not exceeding system's hardware. ARES even detects the number of CPU cores:

But the simulation always is automatically set to a single process:

Hi @Pedro

The FDTD solver does not make use of any CPU parallelization and is actually not very suitable for CPU computation except for very small simulations. It is strongly recommended to run FDTD on GPU to benefit from much higher simulation speeds.