  We simulate the evolution of halo wide binaries in the presence of MAssive
Compact Halo Objects (MACHOs) and compare our results to the sample of wide
binaries of Chaname & Gould (2003). The observed distribution is well fit by a
single power law for angular separation, 3.5" < theta < 900", whereas the
simulated distributions show a break in the power law whose location depends on
the MACHO mass and density. This allows us to place upper limits on MACHO
density as a function of their assumed mass. At the 95% confidence level, we
exclude MACHOs with mass M > 43Msun at the standard local halo density rho_H.
This all but removes the last permitted window for a full MACHO halo for masses
M > 10^{-7.5}Msun.
