# Segmentation Error 11 when running genrestr (KALP-15 in DPPC tutorial)

**URL:** <https://gromacs.bioexcel.eu/t/segmentation-error-11-when-running-genrestr-kalp-15-in-dppc-tutorial/269>\
**Category:** User discussions\
**Created:** [June 8, 2020, 11:45am UTC](https://gromacs.bioexcel.eu/t/segmentation-error-11-when-running-genrestr-kalp-15-in-dppc-tutorial/269 "2020-06-08T11:45:05Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![wcc6571](https://avatars.discourse-cdn.com/v4/letter/w/e5b9ba/32.png) [@wcc6571](https://gromacs.bioexcel.eu/u/wcc6571)\
**Post date:** [June 8, 2020, 11:45am UTC](https://gromacs.bioexcel.eu/t/segmentation-error-11-when-running-genrestr-kalp-15-in-dppc-tutorial/269/1 "2020-06-08T11:45:05Z")

</div>

GROMACS version: 2020.2-MODIFIED (mac)  
GROMACS modification: Yes  
Here post your question  
Hello, I’m currently trying to follow the KALP15 in DPPC tutorial.

When I apply a position restrain, i.e.:  
gmx genrestr -f KALP\_newbox.gro -o strong\_posre.itp -fc 100000 100000 100000

I get the following error:  
Reading structure file  
Select group to position restrain  
Segmentation fault: 11

I read online that this segmentation error may be due to my files blowing up, but I don’t see why this would be the case. But I’m also fairly new to GROMACS.

Any help would be appreciated,

---

<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:** [June 8, 2020, 2:30pm UTC](https://gromacs.bioexcel.eu/t/segmentation-error-11-when-running-genrestr-kalp-15-in-dppc-tutorial/269/2 "2020-06-08T14:30:34Z")

</div>

This has nothing to do with a simulation “blowing up” (physical instability) but is likely a bug. Please file an issue on the GROMACS GitLab site.