MC worked fine on 8.9.4 – I installed 2019.12.4, uninstalled, installed 2019.12 – activity monitor always shows “not reponding” while trying to launch. Have tried to launch from Avid Link as well as directly from applications. I have tried all suggestions I was able to find on forums that address this and now am at a loss. Perhaps try to update to 21.5 as suggested by Job ter Burg in a recent post?
I also separately installed or ran the sentinel driver that no longer comes with the MC install.
AvidLink shows license as : Dongle Licensed Perpetual, expires 12/2021
Issue has been resolved. This resolution would likely have worked with 2019.12.4 but 2021.6 works. I unistalled Avid Cloud whatever. I edited launch agents to keep Avid Link from running (to keep from having to constantly “quit” the app) – MC would not launch as long as it is running.