Hello, Currently I am have a structure which has a ligand bound at less than full occupancy. The ligand in this cause is covalently linked to a CYS residue in the enzyme active site. When the ligand is not present, there are two well conserved waters in the active site in its place. Overall, I have a same space, split occupancy issue. The problem I am having now in phenix 1.7.460 is that I want to refine (simultaneously) these water positions superimposed on the bound ligand position (as both have less than 100% occupancy). However, upon refinement, the waters are always "kicked out" of position and are not allowed to overlay with atoms within the bound ligand. Does anyone know how to get phenix.refine to accept the water and ligands occupying the same coordinate space. Obviously setting the ligand and water positions to sub 100% occupancy does not do the trick. Thanks for any help!! Brandon -- Brandon Goblirsch Research Assistant-Wilmot Lab Biochemistry, Molecular Biology and Biophysics 5-230 Nils Hasselmo Hall Minneapolis, MN 55455 (612)624-0141