  We develop equations and obtain solutions for the structure and evolution of
a protodisc region that is initially formed with no radial motion and
super-Keplerian rotation speed when wind material from a hot rotating star is
channelled towards its equatorial plane by a dipole-type magnetic field. Its
temperature is around $10^7$K because of shock heating and the inflow of wind
material causes its equatorial density to increase with time. The centrifugal
force and thermal pressure increase relative to the magnetic force and material
escapes at its outer edge. The protodisc region of a uniformly rotating star
has almost uniform rotation and will shrink radially unless some instability
intervenes. In a star with angular velocity increasing along its surface
towards the equator, the angular velocity of the protodisc region decreases
radially outwards and magnetorotational instability (MRI) can occur within a
few hours or days. Viscosity resulting from MRI will readjust the angular
velocity distribution of the protodisc material and may assist in the formation
of a quasi-steady disc. Thus, the centrifugal breakout found in numerical
simulations for uniformly rotating stars does not imply that quasi-steady discs
with slow outflow cannot form around magnetic rotator stars with solar-type
differential rotation.
