Updating your Mac to the latest version of the Mac operating system is really easy, and not nearly as time consuming as it used to be. However, there are a few things we recommend you do first to ensure things go smoothly, we run through these, as well as instructions for downloading and installing the latest version of the MacOS in this tutorial. We'll also guide you past the potential headaches and any problems you may encounter.

Here are the steps you should go through when updating your Mac to the latest version of MacOS.

  1. Locate the version of Mac OS you require
  2. Check your Mac is supported
  3. Make sure you have sufficient space
  4. Back up your Mac
  5. Make sure your Mac is healthy
  6. Log into iCloud
  7. Make sure you are on a trusted network
  8. Update to the latest version of your current MacOS version
  9. Download MacOS from the Mac App Store
  10. Install MacOS on your Mac

We also cover how to update your Mac with the more minor updates to the operating system that Apple issues throughout the year at the bottom of this article.

If it's just an update to the current version of the MacOS you need to install jump to this section: Install an update to MacOS

If you want to know how to update your apps on your Mac, read this: How to update all your Mac apps.

Locate the version of Mac OS you require

The first thing you will want to do is find out exactly which version of the Mac operating system to install and make sure that there is no reason not to install it. You can read all about the latest version of MacOS, along with details of the latest point updates and any known issues, here: MacOS Sierra latest news: current version, updates, betas, and new features.

Apple issues a major update to its Mac operating system once a year, previewing it at WWDC in June, and issuing the final version in September, usually. 

During the months from June to September the company will issue beta versions of the next version of the operating system software. Some people will be able to test the beta out on their Macs. It's not just Apple developers who get to try out the new software - if you would like to be a public beta tester your can find out more about that scheme here: How to get the latest MacOS beta.

At the time of writing, macOS Sierra is Apple's latest update to its Mac desktop operating system software. It is available to download for free on the Mac App Store. If you'd like to find out a bit more about macOS Sierra before downloadng it, read our MacOS Sierra review and macOS Sierra vs Mac OS X El Capitan to find out how it compares to the previous version.

Additionally, Apple unveiled MacOS High Sierra at WWDC in June, and it is available now as a public beta should you wish to test it. It will be released as a final version later this year. Find out more about High Sierra here.

Check your Mac is supported

In the case of macOS Sierra, here is a full list of the Macs that will be able to download the MacOS upgrade. You can find out more about the system requirements for macOS here. MacOS High Sierra will be available for the same list of Macs.

  • MacBook (Late 2009 or later)
  • MacBook Air (2010 or later)
  • MacBook Pro (2010 or later)
  • Mac mini (2010 or later)
  • Mac Pro (2010 or later)
  • iMac (Late 2009 or later)

Apple says that you need at least 2GB RAM to run MacOS Sierra, but this is unlikely to be a problem as all the supported Macs have at least 4GB RAM, and these days most Macs have 8GB as standard, some even have 16GB. If you have less than 4GB RAM it is definately time to consider upgrading to a new Mac, or installing more RAM – if you decide to do that, make sure that the RAM you choose is compatible. Read about how to update the RAM in your Mac here.

If you are feeling cautious about installing Sierra on your Mac because your Mac is a little long in the tooth, read: How to install macOS Sierra on older Mac.

You may be concerned that you have some software that you need to use that may not work in the new operating system. Luckily there are a few ways you can try out Sierra without removing an older version of OS X from your Mac, find out How to run macOS on an external hard drive here or partition your hard drive and install MacOS on it, we explain how here: How to dual-boot two Mac Operating systems on your Mac.

Make sure you have sufficient space

Apple suggests that you should have 8GB of free space on your Mac's drive before you install a major macOS update, but we recommend aiming for 15GB to 20GB. The Yosemite installer was 5.16GB, for example, and you'll need to allow some room for temporary files.

If space is looking tight, here's an article about freeing up space on your Mac.

Make sure your Mac is healthy

You should also make sure that your Mac is completely healthy before installing a big update to the system.

Open Disk Utility (in /Applications/Utilities), select your startup drive from the list on the left, click the First Aid tab to the right, and then click Verify. If Disk Utility finds problems, you'll need to boot from a different volume to perform the actual repairs using the Repair Disk button.

Boot into recovery mode (by holding down Command+R at startup) and use Disk Utility from there to perform the recommended repairs.

You can also run the Apple Hardware Test (for Macs older than June 2013) or Apple Diagnostics (for Macs from June 2013 or later). Both tests check your Mac for other hardware issues, such as bad RAM.

Read more about using Disk Repair to fix a Mac here.

Back up your Mac

Before you perform any big update to your Mac - and especially if you are installing a beta - you should back up your Mac and do some other housekeeping tasks which we will address below.

Luckily, Apple makes it easy to back up your Mac using Time Machine, so there is no excuse not to create a Time Machine backup before installing macOS Sierra. We have this article about how to back up your Mac using Time Machine.

Log into iCloud

iCloud is heavily integrated into many Apple apps and system services. Make sure you are logged into iCloud before you start updating and things should go smoothly.

Make sure you are on a trusted network

We advise that you make sure you are on a trusted network - so avoid downloading software in hotels and cafes or any public networks because you don't know what might lurk there.

If you are downloading and installing software we advise that you do so at home, at work, or at your place of education, not on a hotel or cafe network. You will probably find the download is much faster - and downloading at home or could mean you can plug your Mac into the network rather than rely on a wireless download speed (which could mean that the download takes a lot longer!)

You can read more advice about Mac security here.

Update to the latest version of your current MacOS version

Before you upgrade to the new version of MacOS, make sure you install the latest updates to the version of macOS that you're currently running. From time to time there will be software update to improves stability, for example, and there is always a chance that you may have a problem updating to the new version of the Mac operating system if you hadn't pre installed this essential update to the previous version, so do your homework first.

To make sure you are up-to-date, click on the App Store icon in the Dock and select Updates. You can also click on the Apple logo at the top left of your screen and select Software Update from there.

For details of how to install a version update jump to here

You should also make sure you have updated any third party apps too. Those updates may include changes that are required for upgrading to the latest macOS and if you don't run the updates they may not work properly once you have updated.

To update apps you've bought from the Mac App Store, launch the App Store app and click the Updates button in the toolbar. Then click Update All, simply providing your Apple ID and password when prompted.

For apps that you purchased elsewhere you'll need to manually install updates. You can check if there are updates available from the application's menu, in Microsoft Word, for example, it's a case of clicking on Help > Check for Updates.

Check compatibility with your third party apps before updating the macOS. That way you will be up and running immediately, rather than being frustrated by your favorite apps and add-ons not working.

Download MacOS from the Mac App Store

Finally we are onto the exciting stuff, but there's only one potential spanner in the works - you need the Mac App Store.

If you are still running Leopard and don't have access to the Mac App Store you really really really need to upgrade! Current versions of OS X are available only via the Mac App Store and the Mac App Store arrived in Mac OS X 10.6 Snow Leopard. Luckily you can still get hold of a copy of Snow Leopard from Apple. It costs £19.99 and you can buy a copy here: Snow Leopard.

If you open the Mac App Store you will find the latest version of the MacOS.

  1. Launch the Mac App Store (see the Mac App Store icon above)
  2. Search for MacOS (you can also go directly to the macOS Sierra page if you click here).
  3. Click on macOS Sierra (or the version of Mac OS X you require)
  4. Click on Download
  5. Fill out your Apple ID information if prompted
  6. The Installer will start to download, you can see how long it will take if you look at the bar under Downloading
  7. Once the installer file has downloaded a window will pop up on your Mac telling you and asking you to Continue... The Installer file can be found in Applications (but it will open automatically)

Luckily the download happens in the background, so you can continue to work or surf the web.

Install macOS on your Mac

Now that the installer has downloaded you are ready to install the macOS software on your Mac. 

  1. Click on Continue
  2. Follow the on-screen insturctions to finish installing the software update, which should take around half an hour depending on the spec of your Mac

Install an update to MacOS

If you have already installed macOS Sierra and just want to install the latest update to that software you will find it under the Mac App Store updates tab.

  1. Open the Mac App Store
  2. Click on Updates
  3. Click Update besides any updates you wish to install
  4. If the software has not yet been downloaded (you can set it to do this automatically)if will download in the background
  5. Once the software has been downloaded you will see a notification to let you know it is ready to be installed
  6. Your Mac may notify you that it will restart before installing the update, if the timing is bad you can choose to postpone the update for an hour, or until later
  7. When you are ready to proceed, click Update again and wait while your Mac restarts and installs the update
  8. You Mac will shutdown and the installation will commence - beware this can take a while and there is no warning until it actually starts, a recent update was set to take 24 minutes, but panic not - it was probably closer to 10 minutes.
  9. Once the installation has finished your Mac will restart.

How to set up (or disable) automatic downloads on a Mac

You can set your Mac up so that it automatically downloads updates to the operating system.

  1. Open System Preferences
  2. Click on App Store
  3. Select Install macOS updates

Alternatively, deselect that option if you would prefer not to download and install macOS updates automatically.

For information about Apple's terms and conditions for using Sierra read: Should you agree to Apple's terms and conditions.