I have a daemon that can check for and install software updates using softwareupdate. Up to Catalina 10.15.6, the order is softwareupdate --list for each update { softwareupdate --download softwareupdate --install } if any update has Action == restart restart The above has worked so far, but starting with Big Sur beta 5, I was getting infinite loop of download, install, restart. After some trial & error, it appears that in Big Sur whenever Action is 'restart', the --install has to be paired with --restart. For example, updating from beta 6 to beta 7 would be softwareupdate --install macOS Big Sur Beta 7-20A5374g --restart This is not consistent with softwareupdate's man page, which has not been updated since 2012. Anyone else notice this change? I don't know if the pairing --install/--restart is intentional because of the new Update volume, or is a bug that will go away soon. I already files a bug regarding this, FB8700934.