# Fatal error: Topology include file "/usr/local/gromacs/share/gromacs/top/oplsaa.ff/forcefield.itp" n

**URL:** <https://gromacs.bioexcel.eu/t/fatal-error-topology-include-file-usr-local-gromacs-share-gromacs-top-oplsaa-ff-forcefield-itp-n/4381>\
**Category:** User discussions\
**Created:** [June 28, 2022, 8:03pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-topology-include-file-usr-local-gromacs-share-gromacs-top-oplsaa-ff-forcefield-itp-n/4381 "2022-06-28T20:03:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![zizi](https://avatars.discourse-cdn.com/v4/letter/z/a698b9/32.png) [@zizi](https://gromacs.bioexcel.eu/u/zizi)\
**Post date:** [June 28, 2022, 8:03pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-topology-include-file-usr-local-gromacs-share-gromacs-top-oplsaa-ff-forcefield-itp-n/4381/1 "2022-06-28T20:03:20Z")

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GROMACS version: 2021  
GROMACS modification:No  
I receive this error:  
Fatal error:  
Topology include file  
“/usr/local/gromacs/share/gromacs/top/oplsaa.ff/forcefield.itp” not found

is there something wrong with my gromacs like missing a force field file?  
I would appreciate your help.

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**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 28, 2022, 8:16pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-topology-include-file-usr-local-gromacs-share-gromacs-top-oplsaa-ff-forcefield-itp-n/4381/2 "2022-06-28T20:16:03Z")

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Normally one does not spell out the entire path for the force field, `$GMXLIB` is an encoded environment variable, so only `"oplsaa.ff/forcefield.itp"` is necessary in the topology. But the error itself means you did not install GROMACS in `/usr/local/gromacs` so you should probably determine where your installation actually is.

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**Author:** ![zizi](https://avatars.discourse-cdn.com/v4/letter/z/a698b9/32.png) [@zizi](https://gromacs.bioexcel.eu/u/zizi)\
**Post date:** [June 28, 2022, 8:35pm UTC](https://gromacs.bioexcel.eu/t/fatal-error-topology-include-file-usr-local-gromacs-share-gromacs-top-oplsaa-ff-forcefield-itp-n/4381/3 "2022-06-28T20:35:55Z")

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I already ran an other gromacs file and it worked. Plus, it is a computer cluster that lots of users are working with it. I think it is installed perfectly. Any other reason for this issue?