Extensions have been back for a long time. Mac OS 8 is proud. But they’re more thoughtful than they ever were in previous generations. One aspect of how Apple has built these new extensions in, harkening back to the days of old when we got corrupt extensions, is to stage some new extensions. These are the ones we have to enable in the Security & Privacy System Preference pane when we install unsigned software (or the software that tells us it’s inauthentic, as though its whole life is a lie – which it might be).
That software goes into a pair of directories according to the type of extension at /Library/StagedExtensions folder and /Libarary/StagedDriverExtension. The operating system will clear these out as a part of general operating system garbage collection. We can’t manually clear them out because those folders are no longer accessible unless we disable System Integrity Protection ( https://developer.apple.com/documentation/security/disabling_and_enabling_system_integrity_protection ). Luckily, we have a command in /usr/sbin called kextcache that has new options that show up every now. The –clear-staging option will clear those folders. To run it, simply run it as a su:
sudo kextcache --clear-staging