[gmx-users] Fatal error: Cannot find position restraint file restraint.gro

Justin Lemkul jalemkul at vt.edu
Fri Feb 8 15:38:44 CET 2019

On 2/8/19 9:36 AM, Edjan Silva wrote:
> Dear users.
> I can not execute the following command:
> $ gmx grompp -f nvt.mdp -c em.gro -p topol.top -o nvt.tpr
> The error message that appears is:
> -------------------------------------------------------------------------------------------------
> Program:     gmx grompp, version 2019-beta3
> Source file: src/gromacs/gmxpreprocess/grompp.cpp (line 1912)
> Fatal error:
> Cannot find position restraint file restraint.gro (option -r).
>  From GROMACS-2018, you need to specify the position restraint coordinate
> files
> explicitly to avoid mistakes, although you can still use the same file as
> you
> specify for the -c option.
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors
> ----------------------------------------------------------------------------------------------------
> It was not clear how to generate the restraint.gro file.
> I hope everyone helps.

The fatal error is quite verbose. You need to specify the origin of the 
restraints via -r. In previous versions, -r and -c were assumed to be 
the same, but this is no longer the case. My tutorials reflect the new 
requirements. Please check them out, e.g. 



Justin A. Lemkul, Ph.D.
Assistant Professor
Office: 301 Fralin Hall
Lab: 303 Engel Hall

Virginia Tech Department of Biochemistry
340 West Campus Dr.
Blacksburg, VA 24061

jalemkul at vt.edu | (540) 231-3129


More information about the gromacs.org_gmx-users mailing list