This year’s major new version of macOS is all about consolidation rather than the deep structural changes we’ve seen in recent years. That doesn’t mean that it’s only a minor upgrade, though, and careful preparation is needed if you’re going to move up and take advantage of new features, such as Universal Control to integrate your Mac and iPad or automatic text recognition with Live Text.

If you’re already running Big Sur, these changes won’t be dramatic. Apart from the updates to all bundled apps, pretty much everything that ran in macOS 11 shouldn’t miss a heartbeat when you ask it to work in macOS 12.

Although Monterey has more polish and maturity than Big Sur, at its heart it still brings the same fundamental changes, including the “sealed” snapshot System introduced a year ago. It remains on a different planet from Mojave: 32–bit apps can’t run, and others may fail to cope with its separate read–only System volume. If you’re coming to Monterey from Catalina or earlier, you’ll need to make greater and deeper preparations.

If you’ve any doubts about committing totally to Monterey, and need backwards compatibility, consider installing it on an external drive, if you can. That will enable you to drop back to your current macOS when you need, and postpone going the whole way until you’re ready. However, just be aware that this route still upgrades your Mac’s firmware.

Back up your Mac

Backups are vital in case you lose files or need to migrate

Even Carbon Copy Cloner no longer recommends making System volume clones.

Like insurance, backing up before upgrading is essential to ensure you don’t need those backups: when an upgrade goes well, they should seem a waste of time and effort. But try skipping them, or relying on old or incomplete backups, and when something does go wrong you’re likely to lose hours or days as well as some of your most important files.

Backups made before upgrading to Monterey cover three potentially sticky situations. While the installer will always try to join up the new System with your existing Data volume, that may not work out, in which case you’ll need to migrate your documents, apps and other files from your copy or backup.

Updates also bring a lot of reorganization, in the process sometimes dumping files into folders of relocated or rescued items. Your backup enables you to restore anything that goes missing during the upgrade, and to discover where any relocated items came from.