# Topol doesnt exist

**URL:** <https://gromacs.bioexcel.eu/t/topol-doesnt-exist/6777>\
**Category:** User discussions\
**Created:** [July 8, 2023, 4:25am UTC](https://gromacs.bioexcel.eu/t/topol-doesnt-exist/6777 "2023-07-08T04:25:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![cindyawati](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cindyawati](https://gromacs.bioexcel.eu/u/cindyawati)\
**Post date:** [July 8, 2023, 4:25am UTC](https://gromacs.bioexcel.eu/t/topol-doesnt-exist/6777/1 "2023-07-08T04:25:50Z")

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GROMACS version: 2023.1  
GROMACS modification: No  
Here post your question  
Hello, I try protein with ligand simulation. Then I tried to run NVT but I got error like this  
Error in user input:  
Invalid input values  
In option s  
Required option was not provided, and the default file ‘topol’ does not  
exist or is not accessible.  
The following extensions were tried to complete the file name:  
.tpr

my topol.top already available

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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:** [July 8, 2023, 10:22am UTC](https://gromacs.bioexcel.eu/t/topol-doesnt-exist/6777/2 "2023-07-08T10:22:24Z")

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> [@cindyawati](#):
>
> Invalid input values  
> In option s

This means `mdrun` cannot find the file you indicated as input to `-s`, therefore it falls back to looking for the default input file name (`topol.tpr`) and does not find it, either. So the command aborts.

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**Author:** ![shanza](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@shanza](https://gromacs.bioexcel.eu/u/shanza)\
**Post date:** [July 13, 2023, 10:16am UTC](https://gromacs.bioexcel.eu/t/topol-doesnt-exist/6777/3 "2023-07-13T10:16:09Z")

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how we can solve this issue?