α-(1→2)-Mannosidase I from the endoplasmic reticulum (ERManI), a Family 47 glycoside hydrolase, is a key enzyme in the N-glycan synthesis pathway. Catalytic-domain crystal structures of yeast and human ERMan1s have been determined, the former with a hydrolytic product and the latter without ligands, with the inhibitors 1-deoxymannojirimycin and kifunensine, and with a thiodisaccharide substrate analog. Both inhibitors were bound at the base of the funnel-shaped active site as the unusual ¹C₄ conformer, while the substrate analog glycon is a ³S₁ conformer. In the current study, AutoDock was used to dock α-d-mannopyranosyl-(1→2)-α-d-mannopyranose with its glycon in chair (¹C₄, ⁴C₁), half-chair (³H₂, ³H₄, ⁴H₃), skew-boat (^OS₂, ³S₁, ⁵S₁), boat (^2,5B, ^3,OB, B_1,4, B_2,5), and envelope (³E, ⁴E, E₃, E₄) conformations into the yeast ERManI active site. Both docked energies and forces on docked ligand atoms were calculated to determine how the ligand distorts to the transition state. From these, we can conclude that (1) both ¹C₄ and^OS₂ can be the starting conformers; (2) the most likely binding pathway is¹C₄ → ³H₂ → ^OS₂ → ^3,OB → ³S₁ → ³E; (3) the transition state is likely to be close to a ³E conformation.