  An analysis of incoherent photoproduction of $\eta$ mesons off the deuteron
for photon energies from threshold to 800 MeV is presented. The dominant
contribution, the $\gamma$N-$\eta$N amplitude, is described within an isobar
model. Effects of the final state interactions in the $NN$ as well as the
${\eta}N$ systems are included employing models derived within the
meson-exchange approach. It is found that their consideration is important.
Specifically, due to an interference effect the influence of the $\eta N$ final
state interaction is enhanced in the reaction $\gamma d \to np \eta$ close to
threshold.
