I am running a protein ligand MD simulation using gromacs. I have started npt equilibration for 500000 nsteps (1ns). After a computer shutdown at 170500, I started restart using following command:-

gmx_mpi mdrun -s nvt.tpr -cpi state.cpt

but MD started again from step 'zero';

I also used -append option but nothing worked my simulation again start from zero step.

anyone can please suggest me whats wrong I made?

Thanks in advance