[gmx-users] Problems with MD simulations

[Tanos]

    Hi Folks,
    Two of my last MD simulations stopped sundenlly showing the message 
below:

"t = 658.476 ps: Water molecule starting at atom 77348 can not be settled.
Check for bad contacts and/or reduce the timestep.Wrote pdb files with 
previous
and current coordinates
Large VCM(group rest): -339367968.00000, -369255712.00000, 
-340297184.00000, eki
n-cm:  1.51182e+23"

    Does someone knows some reason for this problem and how could solve 
this ???? Should I minimize futher my system ???? What does it means 
"Water molecule can not be settled" ???? How reducing time step could 
help ????

    Tanos Celmar Costa Franca - IME
    Rio de Janeiro - RJ
    Brazil