To perform this action will require booting from a Bootable Installer.
This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Catalina would have to be done on a computer that Qualifies to run Catalina .
If the computer being used to download the Full Version os Catalina id TOO NEW or TOO Old to run Catalina even if to create a Bootable Installer - this computer is Disqualified to perform this action.
The Apple " Licence of Use Agreement " prohibits downgrading to a version of maCO older than what this computer Originally came installed with.
Empty Space - it is suggested to keep at least 15% to 20% of the Drive Total Capacity as Empty Space for good operations of the computer and for additional updates upgrades to download, expand and install.
If this computer doesn't not have the suggest Empty Space Available >>
What is “Other” storage on a Mac, and how can I clean it out?
In Monterey the “Other “ category is named “ System Storage “.
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The final word from Apple on Managing the " Other " Category
Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.