[gmx-users] Using a 4.6.5 cpt file in 5.0 to extend a run?

Nathan Scott scottjn at gmail.com
Thu Sep 25 05:03:53 CEST 2014

Hi all,

I am trying to extend some simulations done on the XSEDE Trestles system
over the summer, and they have upgraded to 5.0 since then from 4.6.5.

Can anyone give any tips for navigating around the below error?

Program mdrun_mpi, VERSION 5.0
Source code file:
line: 2037

Fatal error:
You seem to have switched ensemble, integrator, T and/or P-coupling
algorithm between the cpt and tpr file. The recommended way of doing this
is passing the cpt file to grompp (with option -t) instead of to mdrun. If
you know what you are doing, you can override this error by setting the
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors

In fact, I haven't switched any of the mdp options that were used for the
original simulation, except nsteps, and doing a diff of the mdp file the
original cpt file is based off of and the new one that I am trying to use
to extend the simulation confirms this fact.

Is there a workaround for this? Or might I just be making some kind of
simple mistake? Any advice would be greatly appreciated!

Best Wishes,

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