macOS Big Sur elevates the most advanced desktop operating system in the world to a new level of power and beauty. Experience Mac to the fullest with a refined new design. Enjoy the biggest Safari update ever. Discover new features for Maps and Messages. And get even more transparency around your privacy.

Check compatibility

As the most revolutionary update to Apple’s operating system in years, the macOS 11 Big Sur is a major milestone in macOS history. On Premise (SEC): Sophos Anti-virus for MacOS version 9.10.2 and above have full support for Big Sur, and support for M1 processors via emulation (Rosetta 2).

macOS Big Sur is compatible with these computers:

MacOS Big Sur, the latest version of the world’s most advanced desktop operating system, is now available to Mac users as a free software update. Big Sur introduces a beautiful redesign and is packed with new enhancements for key apps including Safari, Messages, and Maps, as well as new privacy features. The Mac becomes an even better partner to the iPhone and iPad with this upgrade along with the move to Apple Silicon.Subscribe to CNET: https://www.youtube.c.

MacBook introduced in 2015 or later
MacBook Air introduced in 2013 or later
MacBook Pro introduced in late 2013 or later
Mac mini introduced in 2014 or later
iMac introduced in 2014 or later
iMac Pro
Mac Pro introduced in 2013 or later
View the complete list of compatible computers.

If upgrading from macOS Sierra or later, macOS Big Sur requires 35.5GB of available storage to upgrade. If upgrading from an earlier release, macOS Big Sur requires up to 44.5GB of available storage. To upgrade from OS X Mountain Lion, first upgrade to OS X El Capitan, then upgrade to macOS Big Sur.

Make a backup

Before installing any upgrade, 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.

Get connected

It takes time to download and install macOS, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.

Download macOS Big Sur

If you're using macOS Mojave or later, get macOS Big Sur via Software Update: Choose Apple menu  > System Preferences, then click Software Update.

Or use this link to open the macOS Big Sur page on the App Store: Get macOS Big Sur. Then click the Get button or iCloud download icon.

Begin installation

After downloading, the installer opens automatically.

Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.

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.

Allow installation to complete

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 both macOS and related updates to your Mac firmware.

Stay up to date

After installing macOS Big Sur, you will be notified when updates to macOS Big Sur are available. You can also use Software Update to check for updates: Choose Apple menu  > System Preferences, then click Software Update.

Or get macOS Big Sur automatically

If you're using OS X El Capitan v10.11.5 or later and your App Store preferences or Software Update preferences are set to download new updates when available, macOS Big Sur will download conveniently in the background, making it even easier to upgrade. A notification will inform you when macOS Big Sur is ready to be installed. Click Install to get started, or dismiss the notification to install later. When you're ready to install, just open the file named Install macOS Big Sur from your Applications folder.

Learn more

• If the installer shows a list of apps that are not optimized for your Mac, learn about 32-bit app compatibility, then choose whether to proceed with the installation.
• For the strongest security and latest features, upgrade to macOS Big Sur. If you have hardware or software that isn't compatible with Big Sur, you might be able to install an earlier macOS.
• You can also 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.

Many people remember Mac OS X 10.6.8 fondly. Not just 10.6 Snow Leopard, but particularly its very mature 10.6.8 release, the final one in that series. It’s considered a stable and perfectly fine version. It’s not a problem—until they want to mitgrate to a newer computer with the same files, preferences, users, and other elements as their current one. That’s particularly true when they want to keep their system and essentially brain transplant it to the latest two updates, macOS Catalina and Big Sur, and find there’s no direct path.

Apple offers Migration Assistant both when setting up a Mac (whether new or erased) and as an app within macOS, particularly to migrate user accounts and applications. As a source, you can use a Time Machine backup, a disk image copy of your macOS startup volume (via a cloning app, for instance), or another Mac.

But Migration Assistant has its limits: in Catalina and Big Sur, you must migrate from a backup made from or a computer running Mac OS X 10.11 El Capitan or later. Attempts to copy from older installations lead to an error.

However, you’re not stuck. You have several alternatives you can try.

Upgrade past 10.6.8

It may seem like a pain, but if you have a computer that can be upgraded to 10.11 El Capitan or later, that’s your best bet. This list of models from One World Computing will help you figure out if your Mac can be upgraded that far. It covers years of Mac releases. (No Macs that can run Snow Leopard can be upgraded to Catalina or Big Sur, which would solve the problem, too.)

Apple has instructions on installing a terminal release of Mac OS X or macOS for its old computers.

Once upgraded to El Capitan or later, you can then run Migration Assistant to transfer data to Catalina or Big Sur.

Os Big Sur Iso

If your computer’s last OS option isn’t El Capitan, read on.

Os Big Sur Requirements

Copy just the user directory

When spanning such a long gap between releases, you may not need applications or any settings files—you just want to transfer all your document, pictures, and other personal files. In that case, you can use these directions in a Mac 911 column from last year. While that article was written to help you overcome a Migration Assistant failure, it also works when Migration Assistant can’t.

Each of the techniques in that article lets you move the files you need over to a new Mac. The options vary by what your older system is capable of and the level of technical detail you want to cope with.

Install an older Mac OS on an external drive for migration

If the Mac you’re upgrading to (not from) is in the right range of vintages, you can do the following:

Big Sur Compatibility

1. Install Mac OS X 10.11 El Capitan on an external drive. (Download El Capitan from Apple’s site.) El Capitan seems to be the last release that can migrate files from Snow Leopard.
2. Use the Startup Disk preference pane to select that external drive and restart.
3. Use Migration Assistant during setup or after setting up on the external drive to transfer data from your Snow Leopard Mac.
4. Use Startup Disk to restart with your newer Mac’s intended startup volume.
5. Now run Migration Assistant pointing to the external drive.

If you don’t own a Mac that can install El Capitan, you might be able to borrow such a machine from someone and use the same external drive approach that won’t affect the startup drive of their system.

This Mac 911 article is in response to a question submitted by Macworld reader Balthasar.

Ask Mac 911

Os Big Sur Vs Catalina

We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.comincluding screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.