Once the installer has downloaded do not click “Install”.
It might look like an update rather than the full version, but you’ll see from the size of the download (around 6GB) that this is the complete installer for Monterey. Eventually a message “Are you sure you want to download macOS Monterey” will appear. Software Update will open with the words “Finding Update”.Follow the Mac App Store link through Safari to open the Mac App Store on the Monterey page.Follow these steps to download macOS Monterey (or other versions of macOS below) from the Mac App Store:
Apple only replaced Monterey with macOS 13 Ventura in October 2022, but you can still download the installer for Monterey from the Mac App Store.
