I just got this via em@il from Capture One…
"Hold off from updating your Mac OS to 10.15.2, as it will hinder the
tethering functionality in Capture One 12.1.4 and Capture One 20.0.
We're working on a fix as fast as possible. If you've already updated,
please consult Apple Support to find how to revert to an older version
of Mac OS in the meantime."
Regarding tethering and Mac OS 10.15.2 (Catalina)
We are aware of the issues surrounding tethering in Capture One 12.1.4 and Capture One 20.0 when running on Mac OS 10.15.2.
There is currently no workaround for this issue and the only solution we can provide is that you re-install Mac OS to a previous version.
We are working incredibly hard on a fix to try and rectify this issue that has arisen with the latest Mac OS update.