  Every symbolic system supports a Borel measure that is invariant under the
shift, but it is not known if every such systems supports a measure that is
invariant under all of its automorphisms; known as a characteristic measure. We
give sufficient conditions to find a characteristic measure, additionally
showing when it can be taken to be a measure of maximal entropy. The class of
systems to which these sufficient conditions apply is large, containing a dense
$G_{\delta}$ set in the space of all shifts on a given alphabet, and is also
large in the sense that it is closed under taking factors. We also investigate
natural systems to which these sufficient conditions apply.
