The first step to predict aqueous solubilities with the aid of absolute free energy calculations was the assessment of the methodologies we chose to use. Since our method is the same one used by Aragonès et al. and wanted to be sure that we could reproduce previous results, we ran simulations for α-methanol at 150 K and estimated the free energies of solids using MBAR. Turning off the harmonic restraints was the challenging step. Our MBAR calculation of ∆A I E M →solid for α-methanol using 18 intermediate states yielded -18(3) k B T while our TI result was -18.421( ) k B T and the literature result was -17.33(3) k B T using 17 states . The MBAR error was unusually high (3 k B T) which is usually a signal of overlap problems or other serious concerns.