Energy minimisation not getting negative

User discussions
2

It may be because of bad inititial structure, or mdp settings; you can play around it and finish the minimisation but it may not stabilise during equilibration and production. It would be better to provide more informations such as your simulations sytem and how you built it. Also i have seen a lot of questions on such issues in the past and searching on forum will definitly help you to get more on the issues;

https://gromacs.org-gmx-users.maillist.sys.kth.narkive.com/cPNiWR3R/gmx-users-energy-minimization-has-stopped

https://gromacs.bioexcel.eu/t/energy-minimization-error/478