In the past, many of us took the opportunity when upgrading to a major new version of macOS to perform a clean install onto a freshly-formatted disk. In the days when system and user files were all intermingled in the same volume, there were good arguments that the result was worth the extra effort, both in cleaning out the crud accumulated over the years, and in ensuring that we started with a perfect, mint copy of macOS. This article asks what benefits there are to doing this with Monterey or Big Sur, and how you can do it.
Big Sur and Monterey are different from all previous versions of macOS in that the great bulk of macOS is loaded and run from a Sealed System Volume (SSV). That is first installed on the separate System volume, every file checked for integrity, the whole volume ‘sealed’ with a cryptographic hash, and then saved as an immutable snapshot. Every time that system is booted, its integrity is verified against Apple’s master Seal. So as far as the System volume is concerned, there’s nothing to be gained in a clean over a regular install.
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