  3350 objects from the Sixth catalog of orbits of visual binary stars (ORB6)
are investigated to validate Gaia EDR3 parallaxes and provide mass estimates
for the systems. We show that 2/3 of binaries with 0.2 - 0.5 arcsec separation
are left without a parallax solution in EDR3. A special attention is paid to
521 pairs with parallax known separately for both components. We find 16
entries that are deemed to be chance alignments of unrelated stars. At once we
show examples of high-confidence binary systems with significant differences in
the reported parallaxes of their components. Next we conclude that the reported
Gaia EDR3 parallax errors are underestimated, at least by a factor of 3 for
sources with large RUWE. Parallaxes are needed to estimate stellar masses.
Since nearly 30\% of ORB6 entries lack 5 or 6-parameter solution in EDR3, we
attempt to enrich the astrometric data. Distant companions of ORB6 entries are
revealed in EDR3 by analysis of stellar proper motions and Hipparcos
parallaxes. Notably, in 28 cases intrinsic EDR3 parallaxes of the binary
components appear to be less reliable than the parallax of the outer
companions. Gaia DR2, TGAS and Hipparcos parallaxes are used when EDR3 data is
unavailable. Synthetic mass-luminosity relation in the G band for main sequence
stars is obtained to provide mass estimates along with dynamical masses
calculated via Kepler's Third Law.

Solar and Stellar Astrophysics;Astrophysics of Galaxies