# LINCS warning in coarse grained system

**URL:** <https://gromacs.bioexcel.eu/t/lincs-warning-in-coarse-grained-system/10538>\
**Category:** User discussions\
**Tags:** forcefield, mdp-parameters, mdrun\
**Created:** [November 13, 2024, 9:30am UTC](https://gromacs.bioexcel.eu/t/lincs-warning-in-coarse-grained-system/10538 "2024-11-13T09:30:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![girish](https://avatars.discourse-cdn.com/v4/letter/g/e36b37/32.png) [@girish](https://gromacs.bioexcel.eu/u/girish)\
**Post date:** [November 13, 2024, 9:30am UTC](https://gromacs.bioexcel.eu/t/lincs-warning-in-coarse-grained-system/10538/1 "2024-11-13T09:30:13Z")

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GROMACS version:2022.3  
GROMACS modification: No  
Here, post your question: I am trying to simulate a protein + solvent system, but after a certain step, it starts showing the LINCS warning. My protein is coarse-grained using the MARTINI force field. I want to use the time step as 0.02 fs. However, my protein is not stabilized due to its size and poor initial structure. That’s why I have to use 0.005 fs otherwise it shows a LINCS warning.

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**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\
**Post date:** [November 18, 2024, 7:54am UTC](https://gromacs.bioexcel.eu/t/lincs-warning-in-coarse-grained-system/10538/2 "2024-11-18T07:54:18Z")

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Do you mean that your have to use a 0.005 fs timestep to avoid the LINCS warning? Or do you still get the warning?

It is quite common that you have to run (large?) parts of the equilibration with a shorter time step. If you still get a LINCS error, I would suggest having a look at your pressure coupling settings as they can sometimes cause system instabilities.