How-To

How do I upgrade macOS safely?


So, a new version of macOS has just been released and you’re eager to experience it for yourself – but resist the urge to install this update straight away!

Although updating your Mac is usually pretty straightforward and error-free, there’s always a chance that you might be one of the unlucky few who do encounter a problem. Maybe your Mac runs out of disk space halfway through installing the update; you lose Internet connectivity, or your Mac crashes before the installation is complete.

In this article, I’ll show how to reduce your chances of encountering any issues when updating your Mac, so you can install the latest and greatest version of macOS, without any worries!


Be prepared! Always create a backup

Throughout this article, we’ll be looking at steps you can take to avoid all of the most common errors that can occur when updating your Mac. However, even if you follow all of our advice, you may still encounter an issue that’s completely beyond your control. Perhaps Apple’s servers go offline midway through the update process, or maybe you install an early access preview, only to discover that it’s riddled with bugs.

To make sure you’re prepared for any scenario, you should always create a full Time Machine backup before updating macOS.

  • Select the ‘Apple’ logo from your Mac’s menu bar.
  • Navigate to ‘System preferences… > Time Machine.’
  • If this is your first Time Machine backup, then click ‘Select Backup Disk…’ and follow the onscreen instructions.
  • Once Time Machine is configured, navigate back to ‘System preferences… > Time Machine,’ Control-click the disk icon, and then select ‘Back Up Now.’

If you do encounter a problem with your update, then you can revert to this backup without losing any of your important files, documents or data.

Check your third party software

Before installing system-level updates, it never hurts to check that all of your third party apps are up to date. There’s a chance that outdated or buggy apps might interfere with the update process, plus out-of-date apps might stop working once you update to the latest and greatest version of macOS.

To update all of the applications that you installed via the App Store:

  • Open a new ‘Finder’ window.
  • Open the ‘Applications’ folder, and launch the ‘App Store’ application.
  • Select the ‘Updates’ tab.
  • Work your way down this list, selecting the ‘Update’ button for every application that you want to update.

When it comes to applications that you downloaded from outside the App Store, you may have to do some research! You can often find information about potential updates over at the application’s website, blog or social media pages. It’s always worth launching the application in question, to see whether it prompts you to intall any available updates. In addition, many applications have a setting that lets you check for updates manually, so be sure to explore the app’s various menus, particularly any ‘Help,’ ‘Settings’ or ‘About’ menus.

Run Disk Utility

It’s always a good idea to check your Mac for obvious issues, before installing any major updates.

You can get an insight into your Mac’s general health, using Disk Utility:

  • Open a new ‘Finder’ window.
  • Navigate to ‘Applications > Utilities.’
  • Launch the Disk Utility app.
  • In the left-hand menu, select your startup drive.
  • Click the ‘First Aid’ button.
  • When prompted, select ‘Verify.’ Disk Utility will now scan your startup drive.

If Disk Utility does discovers a problem, then you’ll need to boot into a different volume before you can perform the necessary repairs:

  • Power down your Mac.
  • Boot into Recovery Mode by restarting your Mac while holding down the ‘Command+R’ keys.
  • When you see the Apple logo, release these keys.
  • In the ‘macOS Utilities’ window, select ‘Disk Utility.’
  • Follow the onscreen instructions, to perform the recommended repairs.

Do you have enough disk space?

Apple recommend that you have at least 8GB of free space available before installing a major macOS update.

To check how much disk space is remaining on your Mac:

  • Select the ‘Apple’ logo from your Mac’s menu bar.
  • Choose ‘About This Mac.’
  • Select the ‘Storage’ tab.

macOS will now calculate the remaining space. If there’s less than 8GB remaining, then check out our article on how to free up some space, or try Sierra’s optimized storage.

Always use a secure, private network

You should only ever download system updates when you’re connected to a secure, reliable network. If you’re unsure, then you can double-check your network’s security protocols:

  • Select the ‘Apple logo’ from your Mac’s menu bar.
  • Navigate to ‘System Preferences… > Network.’
  • Select your network interface from the left-hand menu, such as ‘Wi-Fi.’
  • Click the ‘Advanced…’ button.
  • Make sure the ‘Wi-Fi’ tab is selected.

This screen contains a list of all the nearby Wi-Fi networks, with each network’s security protocol listed in the ‘Security’ column. If you’re unsure about any of these protocols, then entering the name of the protocol into your favourite Internet search engine will usually return all the information you need.

Don’t rely on battery power

Depending on the speed of your Internet connection and your Mac’s specifications, downloading and installing a new version of macOS can be a time-consuming process.

Even if you have a full battery, it’s always best to play it safe, and make sure your Mac is connected to a reliable power source before starting the update process.

Installing macOS

Once you’ve completed all of these steps, you’re ready to upgrade to the latest release of macOS.

  • Launch the App Store.
  • Select the ‘Updates’ tab.
  • The latest version of macOS should appear under ‘System Updates.’ Click its accompanying ‘Update’ button and then follow the onscreen instructions to download the installer.
  • Once the installer has finished downloading, you’ll typically encounter a popup prompting you to continue with the update process. If you want to go ahead with the update, then click ‘Continue…’ and follow the onscreen instructions. Alternatively, you can return to the update at any time, by navigating to your ‘Applications’ folder, double-clicking the launcher, and then selecting ‘Continue…’

About the author

Jessica Thornsby

Jessica Thornsby is a technical writer based in Sheffield. She writes about Android, Java, Kotlin and all things Apple. She is the co-author of O'Reilly's "iWork: The Missing Manual," and the author of "Android UI Design," from Packt Publishing.

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