# Duplicate atom index error

**URL:** <https://gromacs.bioexcel.eu/t/duplicate-atom-index-error/178>\
**Category:** User discussions\
**Created:** [May 25, 2020, 12:41am UTC](https://gromacs.bioexcel.eu/t/duplicate-atom-index-error/178 "2020-05-25T00:41:37Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![dinesh](https://avatars.discourse-cdn.com/v4/letter/d/a8b319/32.png) [@dinesh](https://gromacs.bioexcel.eu/u/dinesh)\
**Post date:** [May 25, 2020, 12:41am UTC](https://gromacs.bioexcel.eu/t/duplicate-atom-index-error/178/1 "2020-05-25T00:41:37Z")

</div>

Dear all,

I got this error while executing grompp.

**"Duplicate atom index(26) in virtual\_sites3.**

**Duplicate atom index(31) in virtual\_sites3."**

Can anyone help me on how to handle this error?