Hi everyone, I am working on two datasets of the similar crystal design. In one of the datasets, there is an extra guest protein (might be considered as a ligand) docked in one unit cell. The two crystals have very similar unit cell size and same symmetry. I want to calculate the Fo-Fo map to see whether I could figure out where the protein is. But I got error says the symmetry of the two datasets are not the same. I have never used the "isomorphous difference map" in GUI before. Can anyone help me to figure out where I did wrong please? I have attached the mtz file that I want to compare. Btw, if the protein is not very rigidly linked with the crystal framework (~2 free residues linkage), am I supposed to see the density of the protein? Or are there any better ways for me to identify the protein? Thanks for your kind help! Sincerely, Xiang