The metaplectic covering Mp(2n) of Sp(2n) affords an accessible yet nontrivial instance of the Langlands-Weissman program for covering groups. In order to use Arthur's methods in this setting, one needs a stable trace formula for Mp(2n). Thus far, only the elliptic terms have been stabilized. In this talk, I will report an ongoing work on the full stabilization, which is nearing completion. It will hopefully grant access to the whole genuine discrete automorphic spectrum of Mp(2n). Time permitting, I will also try to explain the similarities and subtle differences with the case of linear groups solved by Arthur.