The classic OS X 10.12, or rather macOS upgrade, introduced tons of features anyone would still want on their Mac. Why? Because, it's well-tested and secure. Now we'll take a quick look at the legendary macOS Sierra upgrade. (In case you want to upgrade your Mac to macOS 10.13 High Sierra, check out this guide.)

El Capitan, Sierra, High Sierra, Mojave, Catalina, and now Big Sur, this is really annoying. Personally, I see no advantage in changing OS's because Apple wants to sell more machines. In fact, with every new Apple OS they take something away, like USB faxing, gone forever. Create a New Virtual Machine #1.Now, you have to create a new Virtual Machine. Open the VirtualBox then tap on “New” at the upper left-hand side and name the Virtual Machine “OS X El Capitan“.

Interestingly, it first brought Siri to your Mac. This is great news for everyone who’s already used to her help on iOS. Then, there’s Watch unlocking for Mac, there’s one-click Apple Pay, tabs in apps, and cross-device copypasting. Just to name a few.

So, if you were on the fence about upgrading to Sierra, and in fact, any newer OS, go right ahead. Your Mac deserves a refreshment.

How to upgrade macOS: Sierra 10.12 compatibility list

As with the previous versions, macOS Sierra is available for a limited list of Mac models.
Here are the models of Macs that are compatible with macOS 10.12 and can upgrade to Sierra:

Does order matter when you upgrade macOS?

If your current operating system is OS X Lion (10.7), you can skip a few versions, and upgrade directly to macOS High Sierra. To upgrade to Sierra from, say, Mavericks, you’ll have to consequently upgrade to Yosemite and then to El Capitan first.

Check Your macOS for Sierra Compatibility

These OS versions can upgrade to Sierra:

• OS X Mountain Lion v10.8
• OS X Mavericks v10.9
• OS X Yosemite v10.10
• OS X El Capitan v10.11

Here’s how to find out which OS version you’re running now:

1. Click Apple icon in the top left corner.
2. Choose About this Mac.
3. There you have it, in capital letters.

Memory (RAM): 2 GB (preferably 4 GB)
Sierra is pretty lightweight, so you only need 2 GB of RAM to upgrade. Cool, eh?

Disk space: 8 GB of free space on drive.
In the same About this Mac menu select 'Storage' tab. In front of the multi-colored bar, you will see the phrase, 'X.XX GB free out of XX.XX GB.' If you don't have at least 8 GB of free space, you should delete some old files.

Before you update macOS, don’t forget to:

Clean up your Mac

This is essential if you want a fast and effortless update, and glitchless work of your new macOS. And it’s also pretty easy. To give your Mac a cleanup, you need to get rid of system junk, uninstall extra apps, and clean some old caches. If that sounds like a lot of work, you can get a Mac cleaner like CleanMyMac for the job.

How to update your Mac: Clean it up first

1. Launch it.
2. Hit Scan to find all the extra files you can delete.
3. Press Run.

As you can see, I have 8.56 GB worth of caches, obsolete language files, broken downloads. You'll feel great getting rid of them.
That will give your Mac a basic system cleanup, but CleanMyMac is going to come in handy after the update as well. It monitors your Mac’s health, helps you speed up the system and remove unnecessary apps (Trashing doesn’t fully uninstall apps, by the way).

Back up your Mac

This is basic common sense before any Mac software update you’d like to undertake. Why? Well, because sometimes updates happen less smoothly than you’d like them to. To make sure you have all your information and files saved up neatly, you need a backup. To back up your Mac, you need to activate Time Machine.

• Open your Applications folder.
• Choose Time Machine.
• 'Select Backup Disk…'
  Note: You may need to first choose to 'Set Up Time Machine.'
• Choose where you'd like to store your backup.
• Both an external drive or an Airport Time Capsule fit.

• Switch the toggle on the left, from 'OFF' to 'ON.' Right beneath the name of your storage device, you'll see 'Oldest backup,' 'Latest backup,' and 'Next backup' — Your backup will begin within 5 minutes. To speed it up, click the arrow clock icon next to the Date & Time at the top-right of the menu bar and select 'Back Up Now.'

How to download macOS Sierra (or newer macOS) and install it

macOS Sierra is increasingly becoming a relic. Since 2020, the newest available macOS version is Big Sur. But it all comes down to hardware. Your Mac can only upgrade to the latest version its hardware can support. If your Mac is from around 2012 it can update as high up as to macOS Catalina. If your Mac is from 2010 or older, its limit is macOS High Sierra.

To download any new macOS and install it you’ll need to do the next:
1. Open System Preferences... in the  Apple menu.
2. Click on Software Updates.
On top of the list you'll see the latest macOS version your Mac can download. In our case, it's macOS Big Sur.

Another way to do it is via the Mac App Store.

1. Open App Store.
2. Click the Updates tab.
3. You’ll see macOS updates available for your Mac.
4. Click Update.

Wait for macOS download and installation. Your Mac will restart when it’s done.

Now you have a new OS.
For historic interest, this is how macOS Sierra looked back then when it was still available in the Mac App Store. Now, it can't be found there anymore.

Download macOS installers directly from Apple

Upgrade From El Capitan To Sierra

For users of past operating systems Apple created a handy a list of macOS installers. They go as far back as to macOS Yosemite. The first 3 of them will open and start the update process automatically.

• macOS High Sierra 10.13
  The 3 following installers will download macOS as a disk image (.dmg) After you unpack it, the macOS updater app will appear in your Applications.

We hope this guide has been of use, and don’t forget to clean up your Mac and back it up before you get the classic macOS! Cheers.

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

macOS Big Sur is compatible with these computers:

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.

How To Upgrade From El Capitan To Sierra

Or get macOS Big Sur automatically

Should You Upgrade From El Capitan To Sierra

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.