A prior CSP study of GSK268499B predicted form I as the global minimum with other low-lying crystals possessing intermolecular hydrogen bonding. In that study, a mixed DFT intramolecular conformational energy and empirical intermolecular electrostatic and dispersion model was used to evaluate relative stability of candidate crystal structures. From our CSP calculations using accurate periodic DFT calculations, at 0K and without zero-point energies, the candidate structure matching the experimental form I (RMSD32 of 0.09 Å in reference to CSD structure BIFHOP) is ranked 9th (Figure (d)) using the r 2 SCAN-D3 method, more than 1.0 kcal/mol less stable compared to the lowest energy candidate structure.