The marquee feature of macOS 27 Golden Gate is the long-promised and long-delayed Siri, now called Siri AI.

Unlike the original Siri, the new version—first promised for macOS 15 Sequoia in 2024—has conversational capabilities similar to other modern digital assistants like Alexa and Google Assistant, plus hooks into many parts of macOS and individual apps. It can function as a chatbot in the same vein as ChatGPT or Claude, and can incorporate information from the public web into its responses.

In short, Siri AI is now (close to) what it should have been many years ago, and reasonably on par with its competitors. It’s far more useful, and easier to work with, than any previous version of Siri. Unlike existing chatbots, Siri AI can access your private data—like email, photos, local files, and calendar events—to provide background information for answering questions. Even better, it doesn’t upload your data—Apple says private data doesn’t leave your device—or use it to teach their AI models.

Meanwhile, Apple Intelligence, a collection of features across Apple devices that incorporate Apple’s take on artificial intelligence, has expanded, and the lines between what’s now considered part of Siri and what’s considered part of Apple Intelligence have blurred. Apple appears to be leaning more heavily on the Siri branding for certain features that were previously called Apple Intelligence. In any case, it’s all of a piece now: enabling or disabling Siri (in System Settings > Siri) also enables or disables most of the other Apple Intelligence features.

Siri AI initially operates only in English, and a few features require an M3 or later Mac with at least 12 GB of RAM.

What follows is what is new with Siri AI and Apple Intelligence for macOS 27 users.

• Siri works more like a chatbot now: Activities that previously required an AI chatbot like ChatGPT or Claude, or a smart speaker-based system like Alexa or Google Assistant, can now be handled directly by Siri. You can have more natural and extensive back-and-forth conversations, with Siri being more aware of the context of what you’re asking than it did previously. You can drill down on responses or ask it to refine its results.
• Siri can access the web: As you may have inferred from that example, Siri was using information that wasn’t on my Mac or on Apple’s servers, but rather, “out there” on the web. So, you can ask about nearly any topic, and instead of merely being shown a list of potentially helpful webpages as in the past, now you get the information directly.
• Spotlight and Siri share an interface: In macOS 27, when you press the Spotlight shortcut (⌘-Space by default), you get a text field that serves both purposes (see Spotlight); the gray text in the field even reads Search or Ask. You can type the name of an app or file, and it will give you the same results as Spotlight always has. But you can also ask questions that Siri will answer from its nearly unlimited storehouse of information. Or you can use a plain-language description of what you’re looking for on your Mac and Siri will find it.
• Siri knows more about you: Siri can now understand what Apple calls “personal context,” which is to say, information that can be pulled from the various apps on your Mac—Calendar, Contacts, Mail, Messages, Notes, Photos, Reminders, and so on. That means Siri can incorporate information found in any of those apps into its responses and actions.
• Visual Intelligence comes to macOS: Visual Intelligence was first introduced in iOS and iPadOS, letting your device describe what it saw in a screenshot or the Camera app—or act on it, like extracting information from a poster or a bill. Now your Mac has it, too. This means you can ask Siri about anything on your screen, or have it do something with information on screen. To use this feature, you can simply invoke Siri (for example, by pressing ⌘-Space) and ask a question about something you see on your screen. Or, you can use a new screenshot mode that doesn’t automatically save screenshots. Press ⌘-Shift-6 and highlight a portion of your screen to ask Siri about something in that specific area, or press ⌘-Shift-Space to ask Siri about the frontmost window. Even if you don’t ask Siri anything, it may automatically identify plants, animals, and other elements found in screenshots. (macOS doesn’t yet apply Visual Intelligence to the FaceTime camera or Continuity camera.)

A new switch in System Settings > Siri, Automatic Visual Look Up, is labeled “Identify objects and places that appear in screenshots.” However, I’m unsure what effect this is intended to have, as I am seeing Visual Intelligence hints in screenshots whether or not this switch is turned on.

• The Siri app is new: There has always been an app on your Mac called Siri, but opening it did nothing more than display the Siri field for you to enter a request. Now, however, the Siri app shows you your previous conversations, and even lets you continue them. Siri conversations sync across your devices using iCloud.
• More actions are available: Siri could already take certain actions, such as changing your Mac’s volume or turning VoiceOver on or off. In macOS 27, thanks to an underlying framework called App Intents, Siri can take a much wider set of actions in a larger number of apps. For example, you could ask Siri to send a message in Messages containing the title of the song now playing in Music. Most of Apple’s apps already support actions like these, and third-party apps are getting there.
• You can customize Siri’s voice even more: In System Settings > Siri, click Voice, and you can select a base voice and then drag the Pace and Expressivity sliders as sample responses are played to dial in exactly the tone you prefer.

This feature requires an M3 or later processor and at least 12 GB of RAM.

• Writing Tools look different: If you select text you want to adjust using Apple Intelligence, you no longer see a Writing Tools submenu on the Edit menu or a Writing Tools badge, but rather a Siri badge in most apps, which you can click to reveal the existing tools arranged differently and without the “Writing Tools” label. Some apps give you access to the same tools via a Siri toolbar button.

Apple Intelligence features are currently available in Chinese (Simplified), Chinese (Traditional), Danish, Dutch, English, French, German, Italian, Japanese, Korean, Norwegian, Portuguese, Spanish, Swedish, Turkish, and Vietnamese.

Now that you’ve gone through all the preliminary steps, it’s time to begin the upgrade to macOS 27 Golden Gate. For most people, Plan A—essentially letting the installer do what it wants—is the logical choice. And remember, if it doesn’t work out for any reason, you can always move on later to Plan B, a clean install. Nevertheless, because you may encounter some questions or confusion during the process, I detail exactly what steps to take from start to finish.

Start the installer

Before you run the installer, if you haven’t already done so:

• If you are installing onto a laptop, connect its AC adapter to a power source. (If you forget to do this, the installer will prompt you.)
• Quit all open apps. (The installer attempts to do this for you—and prompts you if it can’t—but you might as well take care of this beforehand.)

To begin the process, double-click the Install macOS Golden Gate icon in your /Applications folder or wherever else you put it. A window appears with just one button: Continue. Click it!

As a reminder, if you chose to use Software Update, there’s no separate installer to run or destination to select.

The Software License Agreement appears next; click Agree, and then click Agree again in the confirmation dialog to proceed.

Select a destination

The next screen—assuming you are using the standalone installer and not Software Update—asks you to confirm which volume you want to install macOS 27 onto. In most cases, it displays its best guess—typically your startup volume—but you may see multiple disks here, in which case you should select the one you want. If the volume where you want to install macOS 27 isn’t visible, you should see a Show All Disks button; click that to display all available options and then make your selection.

If the installer can’t use a volume as the destination for any reason, that volume is dimmed; click it for an explanation. If the volume is empty or contains a recent version of macOS, it should be OK; if not, the instructions may tell you to back it up and erase it. (In some cases you may be prompted to reformat it.)

If you see an “Unsupported partition structure” error message, see what to do when the volume can’t be selected.

With your desired destination volume selected, click Continue or Install (the wording varies depending on your setup). Next, you’re prompted to enter your administrator credentials (in order to add a helper app); do so and click OK (or, in some cases, Unlock).

The installer begins copying files. The copy process typically takes several minutes, but when it finishes, the installer tells you that it will restart your computer automatically in 30 seconds; you can also click Restart to skip the wait. If any apps are still open and the installer is unable to close them automatically (for example, if there are unsaved changes you must respond to), the installer displays a prompt asking you to click Close Other Applications.

Take a meditation break

Depending on a number of variables, including the speed of your Mac and the size of your disk, installation may take less than a half hour or as long as several hours. Apart from the steps you’ve already performed, the process normally requires no intervention until the very end. Until then, you won’t be able to use your Mac for anything else, so now’s a good time to take a break to do some meditation, tai chi, qigong, or yoga—you have a bit of time to kill.

If you insist on watching the installer’s progress bar gradually make its way across the screen, beware: its time estimates (“About 43 minutes,” “Less than a minute,” etc.) are notoriously inaccurate, especially near the beginning and end of the process. And remember: a watched installer never boils.

As the installer progresses, your Mac will restart one or more times, and it may make some unusual sounds (like a long beep). You may also hear your Mac’s startup chime—perhaps even more than once. At the end of the installation, you’ll continue with several additional configuration steps.

When it finishes, Setup Assistant takes over.

The most controversial change in macOS 26 Tahoe, was the new Liquid Glass interface, which greatly increased the use of transparency and glass-like distortion effects that added some glitz to the screen without increasing usability. In many cases, the new appearance made text harder to read, icons more difficult to decipher, and windows more cumbersome to use.

Over subsequent Tahoe releases, Apple made some adjustments to Tahoe to address a few of the most frequent Liquid Glass criticisms. But in macOS 27 Golden Gate, Apple has gone further still, tacitly acknowledging that Liquid Glass went too far the first time around while retaining the overall look and feel introduced in Tahoe.

If you hated Liquid Glass in Tahoe, you’ll probably find it less objectionable in macOS 27, but make no mistake: the user interface looks far more like that of Tahoe than that of Sequoia.

The Liquid Glass slider

In the WWDC keynote introducing macOS 27 Golden Gate, Apple made a big deal about a new slider that ostensibly lets you decide how weak or strong the Liquid Glass transparency effects should be; it appears during installation and can also be adjusted at any time in System Settings > Appearance.

But, in fact, that’s not quite what it does. It merely changes the level of tinting for a handful of interface elements—particularly menus, Control Center, Notification Center, Spotlight, toolbars, and sidebars—that become a bit more or less transparent based on where the slider is set. Instead of having just two choices (Clear or Tinted), as in Tahoe, you can now select any point in the range between the two. But the effect is subtle, and the slider doesn’t change the transparency of the menu bar, Dock, Finder icons, or most other items.

If you want to get rid of most transparency altogether, you must still go to System Settings > Accessibility > Display and turn on “Reduce transparency.” That makes the menu bar, menus, sidebars, and toolbars opaque, while greatly reducing the transparency of the Dock and certain other elements. However, paradoxically, it also removes the shading from sidebars, making them less clearly separated from the rest of the window.

Sidebar improvements

In Tahoe, window sidebars were inset from the window edges, reducing the amount of usable window space. In macOS 27, sidebars once again reach the edge of the window. In addition, macOS 27 brings color back to certain sidebar icons, all of which were uniformly dark gray in Tahoe.

Window improvements

macOS 27 makes two overall changes to windows: showing the active window more prominently and adjusting the corner radius.

In Tahoe, it could be difficult to figure out which window on screen was active. macOS 27 adds cues to make that more evident: the sidebar’s color is darkened, and color icons appear only in the frontmost window.

Another small detail that irritated a lot of people was that Tahoe made window corners much rounder (supposedly to match the curvature of laptop screen corners), which—like the inset sidebars—reduced the amount of usable space in windows. But not all windows got this treatment, meaning some windows had much rounder corners than others, which looked awkward. In macOS 27, all window corners have the same amount of roundness.

Fewer menu icons

Tahoe added icons next to most menu commands, a change with no evident utility (and against Apple’s long-standing human interface guidelines) that made menus more cluttered and inconsistent in indentation. In macOS 27, those superfluous icons are gone, though icons that existed pre-Tahoe are still there.

Updated app icons

Tahoe enforced the rounded-rectangle (or “squircle”) shape for all app icons from Apple and apps downloaded from the App Store. (Apps distributed outside the App Store could optionally work around this requirement.) In addition, Apple’s icons adopted a new look and feel that, unfortunately, also made them less distinctive. The icons haven’t changed dramatically in macOS 27, but they have become crisper and slightly more saturated.

The same slider exists on iPhone and iPad, where it works the same way but changes less; that is covered in how to reduce Liquid Glass transparency in iOS 27.

These six apps gained smaller features in macOS 27 Golden Gate, though two of them close gaps that have annoyed people for years.

Freeform on the Mac

The Freeform app now supports drawing tools, just as many iPhone and iPad apps have done for years (click the Add Drawing button on the toolbar). You can also add folders to organize your boards (click the Folder button on the toolbar), and each folder can be shared with others (hover over the folder name, click the More button, and choose Share). When sharing boards or folders, Freeform may suggest recipients based on the contents of what you’re sharing. In addition, Freeform now supports Dark Mode.

Image Playground on the Mac

The Image Playground app, which lets you alter or create AI images in various styles using a text prompt, now has a much simpler interface. Instead of making you choose a style from a menu, for example, you simply describe exactly what you want. You can also describe changes, and the image adjusts accordingly.

iPhone Mirroring

Previously, the iPhone Mirroring app had only three sizes: Small, Actual Size, and Large. Now, you can resize it by any arbitrary amount, either by dragging a corner with your mouse or by using the zoom controls (View > Zoom In or Zoom Out, ⌘-+ and ⌘-– (minus), respectively).

In addition, you can now, finally, access Control Center on your iPhone from iPhone Mirroring—choose View > Control Center or press ⌘-4. And you can even watch copy-protected videos (such as those from Apple TV) on your iPhone while using iPhone Mirroring.

Journal on the Mac

The Journal app now automatically adds a time stamp to new journal entries, rather than just a date. It also raises the attachment limit (though Apple doesn’t say by how much).

Podcasts on the Mac

When you’re watching a video podcast in Podcasts, there’s now a Hide Video button beneath the progress bar that does just that (while keeping the audio going); bring back the video by clicking Show Video.

Safari on the Mac

Safari has three notable new features, all of which rely on Apple Intelligence:

• Automatic tab grouping: If you go to Safari > Settings > Tabs and choose Automatically Create Topics from the “Organize tabs” pop-up menu, Safari examines the contents of each page and groups them by similarity, reducing the amount of space taken up by open tabs. Click a group to expand its contents.
• Notify Me: Safari can now monitor a webpage and let you know when it changes. To set a notification, click the Page button in the address bar and choose Notify Me. Describe the type of change you’re looking for (such as a new news article or a change in a particular number), click Edit to adjust when and how often Safari should check, and click Done.
• Describe an extension: Can’t find the extension you need? Safari can create a custom extension for you on the fly. It syncs to your other devices via iCloud but can’t be shared with anyone else. To create an extension, click the Page button in the address bar and choose Describe an Extension.

The older the operating system you’re upgrading from, the more changes you’ll notice in macOS 27 Golden Gate—and the greater the likelihood that you’ll encounter compatibility problems with old hardware and software. You’ll find great new features, but you may also have to abandon software you’ve used for many years, adopt new habits, or reorient your thinking about how a Mac works. Before you jump in, you should understand what awaits you.

Read the sections below covering any operating systems you’ve never installed on your Mac.

Changes in Tahoe

In macOS 26 Tahoe, Apple introduced a new numbering scheme that’s now used across all their operating systems; the number represents the year after the operating system is released. Tahoe introduced the somewhat controversial Liquid Glass look and feel, as well as greatly expanded customization options for Control Center and your menu bar. It expanded iPhone Continuity features by bringing the Phone app to macOS, as well as displaying live activities from your iPhone on your Mac’s menu bar. Spotlight was redesigned—not just visually, but also with support for initiating numerous actions without opening an app, jumping right to an action with quick keys, and keeping a history of items you’ve copied to your clipboard. New apps included Apps (which replaced Launchpad), Games, Journal, and Magnifier. Live Translation in FaceTime, Messages, and Phone adds audio and text translation in real time as you type and speak when you’re conversing with someone who speaks a different language. And shortcuts in the Shortcuts app can run automatically on a schedule or in response to various events, while new Shortcuts actions offer a variety of Apple Intelligence features you can use to create more powerful automations.

Changes in Sequoia

macOS 15 Sequoia (along with iOS 18 and iPadOS 18) introduced Apple Intelligence, Apple’s spin on artificial intelligence (AI), with changes to Safari, Siri, Mail, Messages, Notes, Photos, and other apps, plus writing tools throughout the system and optional integration with ChatGPT. It also added window tiling, the iPhone Mirroring app to interact with your iPhone using your Mac, and the Passwords app for easier access to usernames and passwords. Messages gained support for formatted text, animated text effects, scheduled messages, and more flexible tapbacks, while Notes added live audio transcription, collapsible sections, text highlighting, and Math Notes, a simple new way to perform math calculations. Smaller, but (mostly) welcome, changes also appeared in numerous built-in apps, including Calculator, Calendar, Finder, Freeform, Home, Mail, Maps, Music, Photos, Podcasts, Reminders, and Weather.

Changes in Sonoma

macOS 14 Sonoma didn’t look much different from Ventura, but it included a number of useful new features, such as visual reactions and screen-sharing tools for videoconferencing, widgets on the desktop, and significant improvements to Messages, Notes, and Reminders (plus smaller changes in a variety of other apps). It came with Safari 17, which introduced profiles to separate your Safari data into multiple contexts, the capability to turn any website into a standalone app, and a way to share passwords and passkeys securely. Numerous other privacy and security features were included, such as sensitive content warnings, more detailed permissions settings for apps that access your photos and calendars, and alerts about apps that monitor what’s on your screen.

Changes in Ventura

Perhaps the most obvious change in macOS 13 Ventura was the transformation of System Preferences into System Settings, making it look and act much like the Settings app in iOS and iPadOS. This was no mere name change; Apple massively rearranged the names and locations of settings, making them challenging for even a veteran Mac nerd to locate (see what changed in System Settings). Another feature borrowed from iPadOS was Stage Manager, which adds to the existing list of a dozen or so ways to manage apps and windows. (It has proved not to be very popular.)

Safari added a number of small features, most notably support for passkeys, which are the easier, more secure successor to passwords. Mail and Messages gained the capability to unsend messages, and both apps also saw other improvements (such as scheduling messages in Mail and editing already-sent messages in Messages). Photos added a new iCloud Shared Photo Library, which makes it much simpler to share photos within a family, among other features. And a new Advanced Data Protection feature lets you optionally add end-to-end encryption to most iCloud data.

As iPhones are known for their excellent cameras and Macs are not, Apple added a feature called Continuity Camera that lets you use your iPhone as a high-quality webcam for your Mac. Apple also added the new Freeform app for solo or shared whiteboarding. Beyond that, Apple made small changes to numerous system-level capabilities (such as Live Text, Memoji, and Spotlight) and built-in apps (including Clock, Weather, Notes, and Reminders).

Changes in Monterey

Monterey didn’t have a lot of big, flashy features, but it did introduce some important new technologies, such as SharePlay (a way to enjoy synchronized media with someone in another location while chatting using FaceTime), Universal Control (which lets you control multiple Macs and iPads with a single keyboard and pointing device), and Focus (which upgraded Do Not Disturb with user-definable categories, letting you specify who or what can disturb you and when). Monterey also brought Shortcuts to macOS, finally giving Apple users a simple yet powerful cross-platform automation tool. And Monterey was the first version of macOS to support the paid iCloud+ tiers, with exclusive features like Private Relay and Hide My Email.

Safari got a modest overhaul, featuring a revised tab bar, tab groups, better searching, and a redesigned sidebar—plus better privacy protection. FaceTime gained features that help you look and sound better, make better use of group conversations, and even communicate with people using non-Apple devices, while Messages made it easier to find links, photos, and other items people shared with you. The Maps app gained a bunch of new features, including an interactive globe, new driving and transit features, and better searching. Monterey also introduced AirPlay to Mac, Live Text (automatic, instant OCR for images), and Quick Note (to create new notes without opening the Notes app).

Mail on The Mac

Apple says that Mail in macOS 27 Golden Gate has improved, more relevant search results. When you type in the Search field, a banner appears telling you that Mail looks for meaning beyond the specific words you enter, presumably using Apple Intelligence. I can’t say I noticed any improvements during my limited testing, but perhaps those will become more evident over time.

Suggestions may appear, too, when Mail notices something in a conversation that you may want to take action on; Apple’s examples are adding a calendar event or searching for a photo. I have not yet seen these suggestions in my testing.

If you have a bulleted or numbered list in a message you’re composing, you can now choose Remove List Formatting from the Format > Lists submenu or from the Lists pop-up menu to revert the list to regular text.

Messages on the Mac

Messages has improved searching. For example, if you enter a contact’s nickname or a portion of their phone number, the search lists both names and conversations that match, not just individual messages containing that exact text. Searching for media is also reportedly better, though I have so far been unable to produce any good examples.

Like Mail, Messages may offer suggestions as to actions you can take relevant to the current conversation. Smart Replies may also attempt, possibly without success, to mimic your style. And, if a message fails to send, Messages now retries it automatically.

Find My on the Mac

Apple decided in iOS 27, iPadOS 27 and macOS 27 to make the Find My interactions consistent. Previously, you had to click a person, device, or item, then click the Info button on the map to reveal information. It was a fussy way to do it, particularly when you could just tap one of those people or things on an iPhone or iPad and reveal an action sheet, where you could access Directions, Contact, or Play, among other features.

Now, Find My on all three platforms is a single operation: click or tap a person, device, or item in the sidebar to reveal basic information about the location (like Nearby or their distance, street, and city), along with contextually relevant buttons right below it. To get more information, you click or tap the More button for full details, including all the other information previously found on the Info popover.

There’s also a top-level Me tab, giving you more direct access to your own information, something already present for years in Find My for iPhone and iPad.

Maps on the Mac

The Maps app now shows Guides for more locations, and, for certain locations, Satellite view yields more detailed images (enhanced, of course, with Apple Intelligence). I tried zooming in on Apple Park in Cupertino and the improved clarity was quite striking. The same was true for a few other urban locations in the United States that I spot-checked. But all the Canadian locations I tried, including Toronto and Vancouver, looked the same. Whether or when that will change, I have no idea.

Passwords on the Mac

Passwords can already identify passwords that are too weak, or that have appeared in data breaches. Passwords like these that need changing are marked with a red exclamation point and feature a Change Password button that takes you to the appropriate page on the website. macOS 27 takes that concept further, where Passwords automates the process: it goes to the site, chooses a strong new password, saves your new password on the site, and stores the new password in Passwords—all with one click. But this works only on a limited number of sites that support the mechanism Apple requires.

In addition, if “Show password hints” is turned on and you begin typing your password on the Lock Screen, a small question mark button appears to its right. Click that, and a message appears along with a Reset Password button, which you can click if you need to reset your password.

Phone on the Mac

If you’re on a voice call in the Phone app, relevant information, pulled from other apps like Calendar, Contacts, Mail, and Messages using Apple Intelligence, may appear on screen — Call Context. For example, if you’re calling a hotel, you may see the email they sent you when you booked your room.

I have not yet encountered a situation in which I used the Phone app on my Mac and also had contextually relevant information, so I can’t say precisely what this surfaced information looks like.

Home on the Mac

The Home app now offers a single interface in which you can see multiple cameras and search for events, as well as 4K camera recordings.

Additional features Apple announced are synthesized images from multiple cameras and natural-language search. These extras require at least a 2 TB iCloud+ plan, and I believe a 3rd-generation Apple TV running tvOS 27. Neither feature has appeared in testing so far.

macOS 27 Golden Gate updates fewer apps than past versions of macOS did, but three of them gained something worth knowing about.

Finder column sizing and file names

The Finder has two interesting new features, one of which also appears on iPhone and iPad:

• Autosize and reset columns: In column view, right-click or Control-click in any column, choose Show View Options, and check “Resize columns to fit filenames.” The columns autosize to the width of the longest names in each one. Uncheck that box to go back to regular sizing. You can also right-click or Control-click the double-bar handle at the bottom of a column divider to show a menu with Right Size This Column, Right Size All Columns Individually, and Right Size All Columns Equally, where “right size” is Apple’s term for sizing determined by filename length.
• Auto name files and folders: This new Apple Intelligence feature attempts to help you name items. Select a file or folder and press Return to select the name. Hover over it with your pointer and one or more suggested names appear in a pop-up menu. Click one of these to use it as the new name.

If you dislike this feature, you can turn it off: Go to Finder > Settings > General and uncheck “Suggest file names.”

macOS 27 also suggests names for new, untitled documents you create in most apps once they have a bit of content. The suggested names appear in the title bar and in the Save dialog when you save the file for the first time. I’ve found these suggestions to be wildly inaccurate, but your experience may be different.

The naming may also happen automatically when you use AirDrop to transfer files from another Apple device, such as the contents of a screenshot when you AirDrop it from an iPhone to a Mac. In this case, you’re not prompted to approve the name.

Calendar text entry and styled notes

The big change in Calendar is that you can now add and edit events just by giving a textual description. For example, you can click the plus button to create a new event, type “Lunch with Peter at noon on Thursday at Moxies” and Calendar figures out how to translate that into the event you’re expecting. You can later double-click the description and edit it.

I found this feature to be rather hit-or-miss. For example, if I added “and remind me two hours ahead,” that didn’t change the alert time. And if I omitted the time but rather said, “breakfast,” “lunch,” or “dinner,” Calendar unfailingly scheduled the event at 10 a.m.

Another small change in Calendar is support for styled text in notes, which some calendar apps (such as Google Calendar) support. That is, if you’ve used styling such as bold or italics on a note you created somewhere else, that styling appears in Calendar, too.

If you click Edit, Calendar shows you the raw HTML source of the note, which you can adjust as you like.

Although Calendar doesn’t let you directly enter styled text in a note, you can manually enter HTML when you create a note. If you then close the popover or Info pane and reopen it, you see the styled text. And—bonus!—this works even for events on iCloud calendars! In other words, it’s a global feature; it’s just that Apple oddly hasn’t bothered yet to add styling controls to that field.

Notes

Notes has four significant new features:

• Drawing: As in Freeform, drawing tools are available in Notes: click the Add Drawing button on the toolbar.
• Copy as Markdown: You can also use Edit > Copy as Markdown to copy styled text from a note with Markdown tags, ready to paste elsewhere.

Oddly, there is no corresponding Paste as Markdown command.

• Section links: If you use section headings in your note, you can insert links elsewhere in your note that jump to them. Choose Edit > Add Link (⌘-K), choose the section heading from the Link to Section pop-up menu, and click OK.
• Divider lines: Finally, you can now add horizontal divider lines in your notes by choosing Edit > Insert Divider Line (⌘-L).

If you prefer a cleaner installation of macOS 27 Golden Gate than what an in-place upgrade provides—specifically, one that gets rid of any disk errors and gives you a chance to weed out some types of user-created data—opt for Plan B. It’s also the right choice if you tried Plan A and encountered problems.

Much of Plan B is just like Plan A. The differences come at the beginning (erasing your disk manually) and the end (using Setup Assistant to configure numerous settings and, optionally, using Migration Assistant to transfer data from your backup).

Start up from another volume

Unlike Plan A’s in-place upgrade, Plan B requires you to start up from another volume that contains the macOS 27 installer. You have a few choices:

• A bootable installer volume (see how to make one)
• A bootable duplicate stored on an external SSD
• Recovery mode

The first two are covered next; recovery mode follows after.

Start up from an external drive

To start up from a bootable installer volume or a bootable duplicate:

1. Make sure the external drive is connected to your Mac.
2. Choose Apple menu > Shut Down.
3. Press and hold the power button until the text “Loading startup options” appears.
4. Wait for the available startup volumes to appear; this may take 30 seconds or more.
5. Select your external startup volume and click Continue.

Now that you’ve booted from another drive, you can erase your main disk and install macOS 27 onto it.

Start up in recovery mode

To start your Mac in recovery mode, turn it off, then press and hold the power button until you see “Loading startup options” on the screen. When the Options icon appears, click it, then click Continue.

Erase your disk

Having started up from another volume or in recovery mode, follow these steps to erase your destination volume in preparation for macOS 27:

1. Open Disk Utility. If you’ve started up from an external volume, you can find it in /Applications/Utilities. If you’re in recovery mode, click Disk Utility in the macOS Utilities window.
2. If only the volumes are visible in the sidebar and not the drive itself, choose View > Show All Devices.
3. In the sidebar, select the disk or partition you want to erase. (Be sure to select the top-level icon, not an indented container or volume.) If it is not already mounted, click the Mount icon on the toolbar; if prompted to unlock it, enter your password.
4. On the toolbar, click the Erase button.
5. Type a name for your disk, make sure Format is set to APFS, and if the Scheme pop-up menu appears, choose GUID Partition Map.
6. Click Erase.
7. If you see a confirmation dialog, click Erase again. Disk Utility erases the disk, which normally takes just a few seconds. Click Done if prompted when the Erase process is complete.
8. Choose Disk Utility > Quit Disk Utility.

Triple-check to be sure that the volume you’re erasing is the one where you want to install macOS 27, and that it’s the one you’ve backed up following the backup instructions.

You’re now ready to install macOS 27 on the empty volume.

Run the installer

Your next steps are slightly different depending on how you started your Mac:

• If you’ve started from an external drive, make sure you’ve quit all running apps and then double-click the Install macOS Golden Gate icon in your /Applications folder or wherever else you put it. (If you haven’t quit all running apps, the installer will attempt to do so.)
• If you’re running in recovery mode, click Install macOS (or Install macOS Golden Gate).

A window appears with one button: Continue. Click it!

The next few steps are identical to those for an in-place upgrade:

1. The Software License Agreement appears; click Agree, and then click Agree again in the confirmation dialog.
2. Now select your destination. If needed, click Show All Disks to display all available options and click the one you want to use.
3. With your desired destination volume selected, click Continue or Install (the wording varies depending on your setup).
4. Next, you’re prompted to enter your administrator credentials (in order to add a helper app); do so and click OK (or, in some cases, Unlock).

The installer begins copying files, a process that typically takes just a few minutes, but may take longer. Then, depending on your configuration, it may restart your Mac automatically, or it may ask you to click a Restart button. After the restart, the main portion of the installation process occurs.

If you are installing macOS 27 onto a disk that’s encrypted, you may be prompted to enter your password to unlock the disk immediately after the installer restarts your Mac.

The installation itself takes as long as an in-place upgrade does. As the installer progresses, your Mac will restart one or more times, with or without the startup chime. You’ll know the process has finished when the Select Your Country or Region screen appears. That’s part of Setup Assistant.

In addition to the bigger features that each deserved their own chapter, macOS 27 Golden Gate includes dozens of smaller changes, some of which are quite significant. These are the ones that apply to multiple apps or to the system as a whole. Single-app changes are covered separately.

Apple claims many other small improvements, but most are either so minor or described so superficially that there is nothing more to say about them. What follows is only what testing confirmed.

iCloud

Apple is no longer using the term “collaborate” for iCloud sharing in which the live document is shared, as opposed to a static copy. Instead, the command on the pop-up menu is now Share a Link. (Similarly, participants are no longer “Only invited people” but rather “People you choose.”) But the behavior is slightly different now.

If you right-click or Control-click a file or folder in iCloud Drive and choose Share, then choose Share a Link from the pop-up menu, you now see a couple of changes in the interface:

• If you click the text under that menu (“People you choose can view/edit”), the display expands as usual to show who can access the item and with what permissions. But there’s a new “Allow access requests” checkbox here. If you select that, then send a link to a group (as opposed to a single person), each recipient must explicitly request permission to access it, and you must approve that request. Only then is that person added to the Participants list.
• A new Copy Link command appears on the Share menu. If you choose that, a dialog appears, with two options: click Continue to share in the normal way (keeping in mind the extra step described above if you share it with a group), or click Allow Anyone with the Link to copy the shareable link to your clipboard with no constraints on who can use it.

International and multilingual features

Apple is continually expanding macOS’s capabilities to support more languages, keyboards, and regional features. Of course, as a U.S. company, Apple usually releases features in U.S. English first, then slowly spreads them to other languages (and other forms of English). The rate at which this happens is often frustratingly slow, but at least progress is occurring.

Since my knowledge of other languages is insufficient to test most of these features, I can’t tell you much about them, but here’s the list:

• Keyboards are now available for Afrikaans, Basque, Baybayin, Blackfoot, Comanche, Cree, English (Philippines), Galician, Guarani, Kiowa, Luxembourgish, Tsuu’tina, Xhosa, and Zulu.
• Typing suggestions are available for the Vietnamese VNI keyboard.
• Automatic punctuation occurs with most keyboards, regardless of language, with punctuation suggestions appearing as you type in Chinese.
• You can now set the interface language for macOS itself to English (Canada)—woo hoo!—and English (Philippines) in System Settings > General > Language & Region > Preferred Languages.
• Conversion from Pinyin to Simplified Chinese and Kana to, I’m presuming, kanji, has improved. (The way Apple worded this feature on a slide in the WWDC keynote read oddly to me.)
• Live Captions are available in FaceTime for Traditional Chinese.
• Call Recording transcriptions are now available for Traditional Chinese, Japanese, and Brazilian Portuguese, while Live Voicemail transcriptions are available for English (Singapore) and Japanese.
• When you use grammar checking (via Edit > Spelling and Grammar > Check Grammar with Spelling in supported apps), multilingual grammar checking is now supported.
• In Reminders, autocategorization is available for different (unspecified) languages.
• Apple’s feature list also included “Natural language time formats for Chinese and Hindi,” “Holiday-aware alarms in China,” “Chaizi typing,” “Alternate calendars for India support current time zone while traveling,” and “Smart language and keyboard configuration suggestions,” though I don’t know enough about any of these features to describe them further.

Ethernet indicator

When you connect an Ethernet cable to your Mac (which, for laptops, requires an adapter), the Wi-Fi icon on the menu bar changes to an Ethernet icon; clicking this displays information about your Ethernet connection.

Swipe down to refresh

In any app that already has a refresh or reload mechanism (such as Mail and Safari), you can swipe down with two fingers on a laptop’s built-in trackpad, a Magic Trackpad, or a Magic Mouse to refresh the page, just as you would (with one finger) on an iPhone or iPad.

Touch control in Sidecar

Sidecar is a feature that lets you use an iPad as a secondary display for a Mac—either mirroring your Mac’s screen or extending the desktop. That’s a cool trick, but if you wanted to not merely see what’s on your Mac’s display but also control it, Sidecar has always offered extremely limited capabilities. (For example, you could scroll with two fingers but you couldn’t tap individual icons or menu items for Mac apps.)

In macOS 27, Apple has extended Sidecar in such a way that, for the most part, your finger acts as a proxy for your mouse pointer. You can tap any icon or other control, scroll with one finger, use menus normally, and so on.

This feature requires that your iPad also be running iPadOS 27.

Mac news and rumor sites claim this feature isn’t so much about having more control from your iPad, but rather part of the groundwork for a hypothetical future touch-screen Mac, which would presumably allow a similar form of interaction.

The macOS 27 Golden Gate installer doesn’t give you many options, but you can still approach the process in either of two ways:

• Plan A, an in-place upgrade: This easy, default method is appropriate for most people, with some qualifications.
• Plan B, a clean install: Although the installer offers no built-in option to start fresh by erasing your disk, you can accomplish the same thing in a slightly roundabout way.

Most users should start with Plan A and then if (and only if) they encounter problems, move on to Plan B. A few people may want to skip Plan A and go directly to Plan B. In almost every case, the end result will be virtually identical, regardless of which path you take.

Upgrading a new Mac

If you’re not only upgrading a new (or new to you) Mac to macOS 27 but also moving your files from an old Mac, you can use Migration Assistant to transfer your old data to the new Mac. If you use Plan B: Clean Install, Migration Assistant runs automatically at the end of the installation; if you use Plan A: In-Place Upgrade, you can run the Migration Assistant utility immediately after rebooting in macOS 27.

Apple has made a major improvement to Migration Assistant: if it sees an account on the old Mac with the same username as one on the new Mac, it offers to delete the user account from the new Mac and replace it with the data from the old Mac, optionally keeping an archive of the existing account.

Plan A: in-place upgrade

The macOS 27 installer offers a single upgrade method that attempts to make the transition simple by leaving almost all your files, apps, and settings in place. You run the installer as you would any other app, and it replaces all the components of your old macOS installation with their macOS 27 equivalents, while deleting those that are obsolete—just as the App Store app does when it installs minor updates.

The installer automatically checks for certain categories of incompatible software and moves any such files safely aside into a Relocated Items folder in /Users/Shared.

The installer can’t know about every potential software conflict with macOS 27—it disables only software that loads automatically on startup and that runs in the background, such as drivers and other kernel extensions. Ordinary apps are never moved aside, even if they can’t possibly run under macOS 27.

As long as you have a complete backup, you have little to fear from an in-place upgrade to macOS 27, and it’s entirely reasonable for Apple to have made it the only official option.

However, I must reiterate that as good as the installer is, there are no guarantees. Something could still go wrong before, during, or after the upgrade. It’s also possible that, due to an error or design flaw in the installer, important files could be deleted. These are among the reasons to consider following the clean install procedure.

Plan B: clean install

Whether or not you trust the installer (and macOS 27 itself) to protect you from software incompatibilities, you might consider making a fresh start by erasing your entire disk and installing a clean, pristine copy of macOS 27 Golden Gate. This process requires a few extra clicks and a bit more time, but it’s not hard to perform. You must start up from another volume (which could be a bootable duplicate or a bootable installer volume) to erase your previous system, run the installer, and restore your personal files.

The main reason to prefer a clean install over an in-place upgrade is that erasing your disk wipes out any hidden directory corruption, file system problems, and other disk gremlins that may cause problems.

If a clean install did nothing but erase your disk and install macOS 27, then all your settings, user-installed software, and files would be gone, and you’d have to either restore them from a backup or recreate them from scratch: not fun. But as in previous versions of macOS, the macOS 27 installer also offers an optional Migration Assistant feature—available only when you install onto a blank volume—that makes the process easy. As soon as the installation completes, you’ll have the option to migrate all your apps and personal files from another volume. Since you’ve made a complete backup, the installer can take all your personal data from that disk and copy it to the analogous location on the macOS 27 volume.

When copying your old data, you can be somewhat selective, but you can’t select individual files or folders to migrate (or skip). If you select every possible category of data (the default), Migration Assistant dutifully copies virtually everything from your backup to your startup volume (while moving aside any software it identifies as incompatible, just as occurs in an in-place upgrade). Almost to a file, the results should be identical to what you’d get with an in-place upgrade! (There are some tiny differences, but almost certainly nothing you’d ever notice if you didn’t scrutinize every last file on your disk.)

The thing is, I recommend that you do copy all your old data, because otherwise you’re likely to be left without something you need and expect. Therefore, since the net result is essentially the same with the in-place upgrade method and a clean install, I now recommend a clean install only in the following situations:

• Your startup disk has errors that Disk Utility can’t repair, even in recovery mode.
• You want to be selective about which folders and files you let Migration Assistant copy (to reduce the clutter on your disk, for example), and you’re willing to manually copy other files you may need later.
• You’re installing macOS 27 onto a Mac you just purchased, and you want to erase the drive and start fresh. You’ll transfer your data from your old Mac (or PC) during the installation process.
• You attempted an in-place upgrade and it failed.

I want to remind you that Plan B really will destroy all the data on your disk (or partition) prior to installing a fresh copy of macOS 27. If anything were to go wrong with your backup, you would be unhappy. So check your backups!

Pick a plan

To summarize, I believe Plan A is best for most people. Let Apple’s installer do its thing. You’ll already have a full backup (because, remember, I insist on it!), so the worst thing that could happen is you lose an hour or so of your time and have to start over with Plan B’s clean install. The overwhelming probability is that everything will be just fine, however, if you go with the flow.

With any plan—even with an in-place upgrade—questions, choices, and issues may arise. I explain how to deal with all of them as we go.