  The supersymmetric contributions to the Flavor Changing Neutral Current
processes may be suppressed by decoupling the scalars of the first and second
generations. It is known, however, that the heavy scalars drive the stop mass
squareds negative through the two-loop Renormalization Group evolution. This
tension is studied in detail. Two new items are included in this analysis: the
effect of the top quark Yukawa coupling and the QCD corrections to the
supersymmetric contributions to $\Delta m_K$. Even with Cabibbo-like degeneracy
between the squarks of the first two generations, these squarks must be heavier
than $\sim 40$ TeV to suppress $\Delta m_K$. This implies, in the case of a
high scale of supersymmetry breaking, that the boundary value of the stop mass
has to be greater than $\sim 7$ TeV to keep the stop mass squared positive at
the weak scale. Low-energy supersymmetry breaking at a scale that is of the
same order as the mass of the heavy scalars is also considered. In this case
the finite parts of the two-loop diagrams are computed to estimate the
contribution of the heavy scalar masses to the stop mass squared. It is found
that for Cabibbo-like mixing between the squarks, the stop mass at the boundary
needs to be larger than $\sim 2$ TeV. Thus, for both cases, the large boundary
value of the stop masses leads to an unnatural amount of fine tuning to obtain
the correct $Z$ mass.
