  We prove that a quotient singularity $\mathbb{C}^n/G $ by a finite subgroup
$G\subset SL_n(\mathbb{C})$ has a crepant resolution only if $G $ is generated
by junior elements. This is a generalization of the result of Verbitsky [V]. We
also give a procedure to compute the Cox ring of a minimal model of a given
$\mathbb{C}^n/G$ explicitly from information of $G$. As an application, we
investigate the smoothness of minimal models of some quotient singularities.
Together with work of Bellamy and Schedler, this completes the classification
of symplectically imprimitive quotient singularities which admit projective
symplectic resolutions.
