  The stability properties of inviscid protostellar disks are examined taking
into account the Hall effect and buoyancy. Depending on the parameters,
different types of instabilities can exist in different regions of disks. In a
very low ionized region, the instability associated with baroclinic effects of
buoyancy is likely most efficient. The Hall-driven shear instability can lead
to destabilization of regions with a higher ionization. The magnetorotational
instability modified by buoyancy can only be a destabilizing factor in regions
with strong magnetic field or a relatively high conductivity ($\sigma B^2 /
\rho > a_e \Omega$, with $a_e$ the magnetization parameter of electrons).
