# Gromacs Gro file format problem

**URL:** <https://gromacs.bioexcel.eu/t/gromacs-gro-file-format-problem/4858>\
**Category:** User discussions\
**Created:** [September 24, 2022, 3:49pm UTC](https://gromacs.bioexcel.eu/t/gromacs-gro-file-format-problem/4858 "2022-09-24T15:49:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![quantum](https://avatars.discourse-cdn.com/v4/letter/q/b9e5f3/32.png) [@quantum](https://gromacs.bioexcel.eu/u/quantum)\
**Post date:** [September 24, 2022, 3:49pm UTC](https://gromacs.bioexcel.eu/t/gromacs-gro-file-format-problem/4858/1 "2022-09-24T15:49:18Z")

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GROMACS version: 2021  
GROMACS modification: Yes/No  
I have a large gromacs spece.gro file. I am using trjconv to get the spce water position velocities from .trr file. I have noticed this with regular .gro file as well. Why its column 1&2 getting attached after 10000 rows. Please see an example below,

3573SOL OW 9997 3.948 4.918 5.552 -0.5688 0.3562 -0.5804  
3573SOL HW1 9998 3.929 5.014 5.534 -0.7157 0.5941 0.7435  
3573SOL HW2 9999 3.866 4.874 5.589 -0.3718 -0.1701 -0.7598  
3574SOL OW10000 3.924 1.240 1.568 -0.1950 0.9684 0.6467  
3574SOL HW110001 3.968 1.308 1.627 0.0634 1.0487 0.3640  
3574SOL HW210002 3.924 1.151 1.614 -0.1122 1.0584 0.8220  
3575SOL OW10003 4.374 4.506 0.546 0.5154 -0.1469 0.0109  
3575SOL HW110004 4.303 4.535 0.611 0.4903 -1.0085 0.3816

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**Author:** ![cathrine](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/cathrine/32/1736_2.png) [@cathrine](https://gromacs.bioexcel.eu/u/cathrine)\
**Post date:** [September 29, 2022, 12:40pm UTC](https://gromacs.bioexcel.eu/t/gromacs-gro-file-format-problem/4858/2 "2022-09-29T12:40:43Z")

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Hi!  
I’m not sure what the issue is here. Can you specify what kind of error you get?