# Error in Gromacs Command?

**URL:** <https://gromacs.bioexcel.eu/t/error-in-gromacs-command/4131>\
**Category:** User discussions\
**Tags:** simulation-setup\
**Created:** [May 8, 2022, 5:25pm UTC](https://gromacs.bioexcel.eu/t/error-in-gromacs-command/4131 "2022-05-08T17:25:54Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![AmanpreetKaur](https://avatars.discourse-cdn.com/v4/letter/a/dec6dc/32.png) [@AmanpreetKaur](https://gromacs.bioexcel.eu/u/AmanpreetKaur)\
**Post date:** [May 8, 2022, 5:25pm UTC](https://gromacs.bioexcel.eu/t/error-in-gromacs-command/4131/1 "2022-05-08T17:25:54Z")

</div>

I was running the command gmx grompp -f ions.mdp -c 1ua7\_solv.gro -p [topol.top](https://www.researchgate.net/deref/http%3A%2F%2Ftopol.top) -o ions.tpr -maxwarn 1 but I encountered an error stating number of coordinates in coordinate file (1ua7\_solv.gro, 90855) does not match topology ([topol.top](https://www.researchgate.net/deref/http%3A%2F%2Ftopol.top), 90854). How to overcome this . Please help me out . I am attaching both the files and screenshot of the error.

---

<div class="post-metadata">

**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [May 9, 2022, 5:25pm UTC](https://gromacs.bioexcel.eu/t/error-in-gromacs-command/4131/2 "2022-05-09T17:25:05Z")

</div>

The answer to this error is always “you haven’t been keeping track of what is in your system correctly.” If all you’ve got is a protein (or some solute) in water, let `gmx solvate` update the topology with `-p`. If you have other entities in your system that require manual updating in the topology, you simply need to take great care to do this properly.

> [@AmanpreetKaur](#):
>
> -maxwarn 1

Don’t do this :) Trust me, in 99.9% of cases, you’ll regret it.