  We study unphysical features of the BMPV black hole and how each can be
resolved using the enhancon mechanism. We begin by reviewing how the enhancon
mechanism resolves a class of repulson singularities which arise in the BMPV
geometry when D--branes are wrapped on K3. In the process, we show that the
interior of an enhancon shell can be a time machine due to non-vanishing
rotation. We link the resolution of the time machine to the recently proposed
resolution of the BMPV naked singularity / "over-rotating" geometry through the
expansion of strings in the presence of RR flux. We extend the analysis to
include a general class of BMPV black hole configurations, showing that any
attempt to "over-rotate" a causally sound BMPV black hole will be thwarted by
the resolution mechanism. We study how it may be possible to lower the entropy
of a black hole due to the non-zero rotation. This process is prevented from
occurring through the creation of a family of resolving shells. The second law
of thermodynamics is thereby enforced in the rotating geometry - even when
there is no risk of creating a naked singularity or closed time-like curves.
