I am trying to use a reference model in real_space_refinement, but phenix stops with the message: “Cannot not restrain working model to self and a reference model simultaneously” (see below). The reference and working models are identical but bound to different ligands. As far as a I can see, all I am doing is adding the reference model in the input window and ticking the  box for reference model restraints (phenix 1.21rc1-4985).

Best wishes,

Luca