Upgrade From Mountain Lion To Sierra



Upgrade to macOS Big Sur

Before installing this upgrade, make sure that your Mac is ready.

Check compatibility

MacOS 10.13 High Sierra was released to the public on September 25, 2017. Like OS X El Capitan and OS X Mountain Lion, High Sierra is a refinement-based update having very few new features visible to the user, including updates to Safari, Photos, and Mail, among other changes. Safari automatically keeps an eye out for any saved passwords that may have been involved in a data breach. Using advanced cryptographic techniques, Safari periodically checks a derivation of your passwords against an updated list of compromised credentials. If a breach is discovered, Safari helps you upgrade your existing passwords.

Sierra

macOS Big Sur supports most Mac models introduced in 2013 and later.

View compatible Mac models

Make a backup

Before you upgrade, make a complete backup with Time Machine, or store your files in iCloud.

Learn how to back up your Mac

Free up space

If the installer needs more storage space to upgrade, you can free up space using tools that come with your Mac.

Free up storage space

Download macOS Big Sur

If you’re using macOS Mojave or later, choose Apple menu  > System Preferences, then click Software Update. If you’re using an earlier macOS, use the App Store instead.

Learn how to download and install macOS Big SurGo to the App Store

Get to know macOS Big Sur

Learn about some of the new features of macOS Big Sur.

Control Center

Control Center brings favorite controls such as Bluetooth, Wi-Fi, Do Not Disturb, and Sound together in a single place—so you can easily adjust them at any time.

Use Control Center

Notification Center

Notification Center puts notifications and>

Lion

Safari

Customize your start page, navigate with ease using the new tab bar, and access a new privacy report to see just how Safari protects your privacy as you browse.

Get to know Safari

Maps

Discover great places around the world and navigate easier with guides, cycling directions, indoor maps, Look Around, electric vehicle routing, and more.

Messages

Send messages to friends and family using new tools that make it easier to keep track of group conversations and give you fun, engaging ways to express yourself.

Use MessagesLearn more on YouTube

Photos

Upgrade From Mountain Lion To Sierra

Use the expanded editing capabilities in Photos to easily make simple changes and more advanced adjustments to your photos.

Learn how to edit your photos

Have a question?

Ask everyone. Our Apple Support Community can help you find answers.

Ask now

Tell us how we can help

Answer a few questions and we'll help you find a solution.

Get support

To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.

Learn how to upgrade to macOS Big Sur, the latest version of macOS.

Check compatibility

If a macOS installer can't be used on your Mac, the installer will let you know. For example, it might say that it's too old to be opened on this version of macOS, or that your Mac doesn't have enough free storage space for the installation.

To confirm compatibility before downloading, check the minimum requirements for macOS Catalina, Mojave, High Sierra, Sierra, El Capitan, or Yosemite. You can also find compatibility information on the product-ID page for MacBook Pro, MacBook Air, MacBook, iMac, Mac mini, or Mac Pro.

Make a backup

Before installing, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.

Download macOS

It takes time to download and install macOS, so make sure that you're plugged into AC power and have a reliable internet connection.

Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.

  • macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
  • macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
  • macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion

Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.

  • macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
  • OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
  • OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard

Install macOS

Follow the onscreen instructions in the installer. It might be easiest to begin installation in the evening so that it can complete overnight, if needed.

Mountain

Can I Upgrade Directly From Mountain Lion To High Sierra

If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.

Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs macOS and related firmware updates.

Learn more

Can I Upgrade From Mountain Lion To High Sierra

You might also be able to use macOS Recovery to reinstall the macOS you're using now, upgrade to the latest compatible macOS, or install the macOS that came with your Mac.