# Restaring simulation in gromacs

**URL:** <https://gromacs.bioexcel.eu/t/restaring-simulation-in-gromacs/1086>\
**Category:** User discussions\
**Created:** [November 14, 2020, 3:19pm UTC](https://gromacs.bioexcel.eu/t/restaring-simulation-in-gromacs/1086 "2020-11-14T15:19:21Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![nadimferdous32](https://avatars.discourse-cdn.com/v4/letter/n/9d8465/32.png) [@nadimferdous32](https://gromacs.bioexcel.eu/u/nadimferdous32)\
**Post date:** [November 14, 2020, 3:19pm UTC](https://gromacs.bioexcel.eu/t/restaring-simulation-in-gromacs/1086/1 "2020-11-14T15:19:21Z")

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GROMACS version: 2020.2  
GROMACS modification: Yes/No  
I tried to run a 500ns simulation using Gromacs 2020.2. But due to a power cut, my pc stopped and the simulation was terminated after about 450 ns. How can I resume the simulation now?  
I do not have the cpt file that can be used to resume the simulation!

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**Author:** ![pjohansson](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/pjohansson/32/316_2.png) [@pjohansson](https://gromacs.bioexcel.eu/u/pjohansson)\
**Post date:** [November 15, 2020, 7:42am UTC](https://gromacs.bioexcel.eu/t/restaring-simulation-in-gromacs/1086/2 "2020-11-15T07:42:38Z")

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Hello,

if you do not have the checkpoint file, but do have a trajectory with velocities, you can extract the last frame from that and start a new simulation from that time step. Use the `gmx grompp -t` flag. Per the documentation, it should take the last saved frame from it when creating the new `.tpr` file.

Regards,  
Petter