Our susceptibility studies of the frustrated magnet Yb2Sn2O7 has revealed a spin glass transition of the Yb3+ magnetic lattice at T_g = 140 mK. To our knowledge, this constitutes the second only realization of such behaviour in a disorder-free magnetic system, the other one being Y2Mo2O7. The origin of this behaviour is still controversial and muSR have been key to show the existence of certain degree of local disorder that could explain the spin glass ground state. The freq. dependence of Tf makes Yb2Sn2O7 a canonical spin glass. However, certain features such as the lack of a memory effect and field depence of Im. Chi suggest a more complex scenario. In the experiment we intend to perform a full study of the magnetic ground state in Yb2Sn2O7: does it show the expected spin glass behaviour? what is its behaviour on an applied magnetic field? For this we apply for 3 days of MuSR time.