I think that your root version is not updated enough: on the Gate website it's stated that version 4.0.0 needs root version 5.14 to last, and you have 5.12. Edoardo >My Gate condition > Gate_v4.0.0 > clhep-2.0.3.2 > geant4.9.1.p02 > root_v5.12.00 > lmf_v3.0