In cases where the binding site showed high water occupancy (runs 1, 2, and 4), the resultant strain favoured vanishing of the ligand, producing divergence of the vanish stage PMF towards more favourable free energies of vanishing. The opposite was true for runs 3 and 5, which had very low average water occupancies at λ = 0.4. This is in accord with the results of Rogers et al., who found negative correlation between water occupancy and the gradient of the potential energy with respect to λ at intermediate stages of the vanishing leg.