On the Mac you want to upgrade to Monterey, do one of the following: There are two easy ways to download the complete installer for MacOS Monterey.
Step 1: Download the full MacOS Monterey installer on the Mac you want to upgrade The simplest way to upgrade directly to a particular release of MacOS is to download the full installer for that system software release you wish to run, and upgrade to it directly. How to Upgrade from Older MacOS (Catalina, Mojave, Big Sur) to MacOS Monterey (And Avoid Ventura)
This is a particular scenario that some Mac users find themselves in, so we’re going to cover the process of upgrading an older MacOS version to MacOS Monterey directly, while avoiding installing the latest release of MacOS Ventura.
