  Gravitational microlensing may detect dark stellar remnants - black holes or
neutron stars - even if they are isolated. However, it is challenging to
estimate masses of isolated dark stellar remnants using solely photometric data
for microlensing events. A recent analysis of OGLE-III long-timescale
microlensing events exhibiting the annual parallax effects claimed that a
number of bright events were due to "mass-gap" objects (with masses
intermediate between those of neutron stars and black holes). Here, we present
a detailed description of the updated and corrected method that can be used to
estimate masses of dark stellar remnants detected in microlensing events given
the light curve data and the proper motion of the source. We use this updated
method, in combination with new proper motions from Gaia EDR3, to revise masses
of dark remnant candidates previously found in the OGLE-III data. We
demonstrate that masses of "mass-gap" and black hole events identified in the
previous work are overestimated and, hence, these objects are most likely
main-sequence stars, white dwarfs, or neutron stars.
