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Should you upgrade to macOS 27? What to check first

Mac IQ | Mac advice | New Zealand
Information checked: 2 November 2026

macOS 27 is out ahead of 2027 and is now at 27.2, with fixes already issued. For most people with a compatible Apple-silicon Mac, upgrading is a reasonable choice. But before you click install, check that the apps, printer and other equipment you rely on will keep working.

The short answer

If you use mainstream apps, your Mac is backed up, and your essential devices are confirmed to work with macOS 27, upgrading is sensible. Apple has already issued bug fixes and security updates, so you are not installing the first release-day version.

If your Mac runs specialist business software, an older printer or scanner, or an Intel-only app that you cannot do without, check with the software or equipment maker first. If you cannot confirm support, waiting is a safer choice than risking an interruption to your work.

First, check whether your Mac is supported

macOS 27 supports Apple-silicon Macs; Intel Macs are not on Apple’s compatibility list. The useful check is the chip in your Mac, not just its year. For example, some 2020 Macs have Apple silicon and are supported, while some 2020 Intel models are not.

Open About This Mac to check your model and chip, then compare it with Apple’s macOS 27 compatibility list. If macOS 27 appears in Software Update, that is a good sign that your Mac can install it. It does not check whether your particular apps, printer, scanner or accessories are compatible.

Check the things you rely on

Before upgrading, write down the handful of apps and devices that would cause a problem if they stopped working. Check each one against its maker’s macOS 27 support page or release notes.

  • Work apps: Check the exact version you use, especially accounting, point-of-sale, practice-management, design, VPN, security and backup software. “Runs on Mac” is not the same as “tested with macOS 27”.
  • Printer and scanner: Check the manufacturer’s support for your exact model. Confirm printing and scanning—a printer working does not guarantee its scanner utility will. If the printer supports AirPrint, Apple says you can print without installing a separate driver; still check scanning and any special functions with the manufacturer.
  • Accessories: Check the apps and firmware for docks, audio interfaces, webcams, label printers and other equipment that needs its own driver or control software.
  • Shared work systems: If you use a business server, NAS, remote-access tool or specialist cloud service, confirm its Mac client and any helper software support macOS 27.

If the maker has not confirmed compatibility for something essential, keep using your current macOS for now and check again later.

Will the upgrade slow your Mac down or use too much space?

There is no strong, controlled public test showing that macOS 27 makes every older supported Mac slower. One reviewer reported quicker everyday use on an M1 Max Mac Studio and an M4 Max MacBook Pro, but those were observations rather than a benchmark comparison. Another review found the system used more disk space than the previous macOS on its test Mac.

That extra space is a storage consideration, not proof that your Mac will run more slowly. Apple does not publish a single free-space figure for every Mac and setup. One third-party preparation guide suggests around 40GB free as a working target; treat it as a rule of thumb, not Apple’s minimum. If your drive is nearly full, free up space before starting rather than relying on the installer to make room.

After any major macOS upgrade, give your Mac time to finish its background work before judging its speed or battery life. If serious problems continue after the initial settling-in period, investigate them rather than assuming they are normal.

What you get with macOS 27

The headline changes include a more capable Siri and Apple Intelligence features, along with updates to search and built-in apps. Some features depend on your Mac’s hardware, language and region, so not every Mac will get every capability. This is the short version; keep an eye out for our separate article looking at the new features in more detail.

What about Rosetta and older apps?

Rosetta lets Apple-silicon Macs run many apps written for Intel Macs. Apple says it remains available as a general compatibility tool through macOS 27. Its release notes also say Rosetta is no longer removed during an upgrade.

You should not need to reinstall every Intel app just because you upgrade. However, check with the app maker if an older Intel-only app is essential to your work. If the app asks to install Rosetta, follow Apple’s prompt; if the app still will not open, check for a supported update or contact its maker before relying on it.

Before you install

  1. Check Mac compatibility on Apple’s list and confirm your chip in About This Mac.
  2. Check your essential apps, printer, scanner and accessories with their manufacturers.
  3. Make a fresh backup. Apple recommends a Time Machine disk with capacity ideally at least twice your Mac’s storage. Check that the latest backup completed, and make sure you can browse or restore a file.
  4. Leave enough free storage. Around 40GB is a practical target, not an official requirement. Free up more if your Mac’s drive is nearly full.
  5. Choose a quiet time. Plug in your Mac and avoid starting the upgrade just before a deadline or busy workday.
  6. Test your setup afterwards. Open your key apps, print and scan, connect to your VPN or shared files, and check that your next backup runs.

So, should you upgrade?

For most people with a compatible Apple-silicon Mac, current everyday apps and a recent backup, macOS 27 is a reasonable upgrade. The initial release has had fixes, and there is no solid evidence that the larger operating system automatically makes a supported Mac slower.

If your work depends on a specialist app, older printer or Intel-only tool, verify support first. If you cannot confirm it—or cannot afford any disruption—wait. The update can wait until your setup is ready.

If you are unsure whether your Mac or work software is ready, Mac IQ can help you check before you upgrade.

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