  HR 6819 was recently reported to be a triple system with a dormant black hole
(BH). The inner binary system was defined as a star estimated to be at the end
of its main sequence and a dormant BH. As the inner binary is not resolved, the
third component may actually just be spatially coinciding with the inner
binary. In this study we test whether the system inner binary can be
reconstructed using the isolated binary evolution in the Galactic field or
through the dynamical evolution within globular star clusters. Our goal is to
understand the formation of the HR 6819 inner binary. To simulate the inner
binary evolution we assumed that the influence of the third body on the inner
binary is negligible. We created synthetic populations of BH main-sequence
binaries for the Galactic disc and the Galactic globular clusters to compare to
the reported parameters of the HR 6819 inner binary. We have adopted very
optimistic input physics, in terms of common envelope evolution and BH
formation, for the formation of binaries similar to the reported inner HR 6819
binary. Despite our optimistic assumptions we cannot form systems like the
inner HR 6819 binary in globular clusters. Even with our extreme assumptions,
the formation of an HR 6819-like binary in the Galactic field population is not
expected. We argue that if a dormant BH actually exists in the reported
configuration inside HR 6819, its presence cannot easily be explained by our
models based on isolated and dynamical binary evolution.
