macOS Big Sur – What are the New Features?

What better way to start the day other than with a major update for your favorite device? With that being said, we have some amazing news to share with Mac users! Apple has finally decided to roll out the much anticipated macOS Big Sur. This is the latest operating system update for Macs and it comes with a bundle of software and security improvements that enhancing the overall performances of Macs that are eligible to download macOS Big Sur.

How to Download macOS Big Sur

The new macOS Big Sur update is a high-priority release and we are advising all Mac users to get it as soon as possible. The great thing about this is that users don’t need to do anything else other than to keep their devices connected to a stable Wi-Fi network. The update will automatically pop up. If this doesn’t happen, then the update can always be manually triggered by accessing the “Software Updates” menu in the Settings panel.

Full Patch Notes

macOS Big Sur interface

Check out the list below to see all the improvements that macOS Big Sur introduces:


Known Issues

  • You might be unable to pair certain braille displays using Bluetooth. (69794099)

Workaround: Connect these devices using USB instead.


App Store

New Features

Core ML


  • The default initializer on the auto-generated model interface has been deprecated in favor of init(configuration:). Please use init(configuration:) or the newly introduced .load() method and handle model load errors as appropriate. (64432588)

Installer and Software Update

Known Issues

  • When updating from macOS Big Sur 11 beta 2 to macOS Big Sur 11 beta 3 or later, you might be offered an unexpectedly large download rather than an incremental software update. (65753086)

Workaround: Under the “Another update is available” text, click the “More info…” link. This reveals the incremental update where you can click the Install Now button.

  • You might need to adjust Energy Saver settings so your Mac doesn’t go to sleep while preparing to install macOS Big Sur 11.0.1. (63166401)
  • If macOS Big Sur 11.0.1 is installed into the same APFS container as previous versions of macOS Catalina 10.15, system software updates can no longer be installed on the previous versions of macOS. (64411484)

Workaround: Update the previous version of macOS Catalina to 10.15.6 or later.


Known Issues

Workaround: During development, you can temporarily disable System Integrity Protection to allow these deprecated kernel extensions to load.

  • New in macOS Big Sur 11.0.1, the system ships with a built-in dynamic linker cache of all system-provided libraries. As part of this change, copies of dynamic libraries are no longer present on the filesystem. Code that attempts to check for dynamic library presence by looking for a file at a path or enumerating a directory will fail. Instead, check for library presence by attempting to dlopen() the path, which will correctly check for the library in the cache. (62986286)
  • Use only absolute paths with the –volume-root option of kmutil, and don’t use a trailing /. (63773848)
  • Symbols exported by both xnu and Apple kernel extensions will change. Recompile your kernel extension with each update to macOS Big Sur 11.0.1 to ensure compatibility. (64262563)

New Features

  • The kern.argmax limit has been increased, allowing programs to receive longer argument lists. (48661669)
  • Darwin kevent now allows non-parent processes to register for NOTE_EXITSTATUS, which delivers the same values as the wait() family of functions in the event data. Refer to the wait4() man page for more information. This event is subject to the following security checks:
    • The requesting process is allowed to send signals by sandbox restrictions.
    • The requesting process and the target process are running as the same user or the requesting process has root privileges. (58134463)


  • Kernel extensions using certain deprecated KPIs no longer load. Refer to the support page. While macOS Big Sur remains in development, you can temporarily disable System Integrity Protection to allow these deprecated extensions to load. (55068348)

Key-Value Observing

New Features

  • Key-Value Observation removal facilities now employ deterministic bookkeeping methods. Cases that would have produced hard-to-diagnose crashes, especially those where KVO signals problems accessing deallocated observer pointers or observers associated with incorrect objects, now produce an exception pinpointing which observed object needs a missed removeObserver(_:) call, and by which observers. This exception was previously thrown as ‘best effort’ when KVO could detect the problem; the new deterministic bookkeeping allows it to be thrown for all cases where removeObserver(_:) is needed.

The improved determinism also allows improved Swift API handling. Instances of NSKeyValueObservation, produced by the Swift NSObject.observe(_:changeHandler:) method, take advantage of integration with this bookkeeping so they now invalidate automatically when the observed object is released, regardless of how the object implements its KVO behavior. This applies to all usage of this API in macOS 11 Big Sur beta, including on processes built with previous versions of the SDK, and eliminates certain classes of crashes that sometimes required using the legacy API instead. (65051563)


New Features

  • New APIs are available for using os_log from Swift as part of the os framework:
    • A new type Logger can be instantiated using a subsystem and category and provides methods for logging at different levels (debug(_:)error(_:)fault(_:)).
    • The Logger APIs support specifying most formatting and privacy options supported by legacy os_log APIs.
    • The new APIs provide significant performance improvements over the legacy APIs.
    • You can now pass Swift string interpolation to the os_log function.

Note: The new APIs can’t be back deployed; however, the existing os_log API remains available for back deployment. (22539144)

Mac Catalyst

Known Issues

Use conditional code that respects the targeted platforms to avoid these exceptions. For example, an iOS app with an Optimized for Mac version available on macOS Big Sur 11, and an iPad idiom version available on macOS Catalina could style a UISlider as follows:

func style(_ slider: UISlider) {    if slider.traitCollection.userInterfaceIdiom != .mac {        slider.setThumbImage(customThumb, for: .normal)        slider.setThumbImage(customThumb, for: .disabled)        slider.maximumTrackTintColor = .clear    }}

A Mac Catalyst app targeting solely iOS and Optimized for Mac versions could conditionally compile the code as follows:

func style(_ slider: UISlider) {    #if !targetEnvironment(macCatalyst)        if slider.traitCollection.userInterfaceIdiom != .mac {            slider.setThumbImage(customThumb, for: .normal)            slider.setThumbImage(customThumb, for: .disabled)            slider.maximumTrackTintColor = .clear        }    #endif}

This helps ensure that your app won’t see unexpected configurations or appearances, if these behaviors change. Use caution when reading the userInterfaceIdiom from a UIDevice or UIScreen to guard Mac idiom behaviors in case your app targets CarPlay or uses AirPlay to stream to another screen.

  • The button configuration for the preferredAction is the default button with the key equivalent of return.
  • The button configuration for the action with UIAlertAction.Style.cancel has the key equivalent of escape.
  • Button configurations for actions with UIAlertAction.Style.destructive will be configured with hasDestructiveAction.
  • If you apply both preferredAction and UIAlertActionStyleCancel to the same action, preferredAction takes precedence. It’s not possible to have a default button with the escape key equivalent.
  • The system adds an Open Recent menu automatically to applications that support opening files. The menu identifier is UIMenuOpenRecent.
  • UISceneActivationRequestOptions has a new collectionJoinBehavior property. A scene collection is a group of scenes that display together. In Catalyst, this is used to add windows to an NSWindowTabGroup.
  • UISwitch has a new preferredStyle property that can alter the appearance of the switch in Catalyst apps running in the Mac idiom, see Optimize the Interface of your Mac Catalyst App — WWDC20 for more information.
  • Set the preferredstyle value to UISwitch.Style.sliding to give the traditional iOS switch appearance; it will look like a native switch in Optimized Catalyst apps.
  • Set the preferredstyle value to UISwitch.Style.checkbox to give a traditional macOS checkbox in optimized Catalyst apps. When set to the checkbox style, the system displays the new title property in a label within the clickable bounds of the checkbox. The title property is inert with the sliding style.
  • The UISwitch preferredstyle property defaults to automatic and renders as a sliding switch in all idioms except the Mac idiom — the only idiom where the checkbox is available.
  • A notable consequence of this default style of the sliding switch is that if you’re using the checkbox style UISwitch, you may need to call sizeToFit() or provide a frame through other means where the intrinsic size alone was sufficient.
  • The default context menu presented from a UITextView or UITextField has missing items related to spelling and formatting.
  • The text you use in a UITextView or UITextField to look up definitions may be out of sync with the visual selection.
  • UITitlebar has a new UITitlebarSeparatorStyle property that gives control over the appearance of the hairline bar in between a macOS window’s titlebar and its content. This property is especially useful when designing interfaces in the style of the new macOS Big Sur full-height sidebar.

New Features

  • Optimized for Mac is a new option for Catalyst apps. When optimized for Mac, Catalyst apps use Mac controls, appearances, spacing, and true font metrics, and content is no longer scaled by 77 percent. A new constant, UIUserInterfaceIdiom.mac, has been introduced to support the new idiom. For more information on the new idiom and optimizing your Mac Catalyst app, see Choosing a User Interface Idiom for Your Mac App, and Optimize the Interface of your Mac Catalyst App — WWDC20.
  • When you deliver your iPad app on the Mac via Catalyst, your existing users on iOS no longer need to purchase your app a second time. In addition, you can manage the capabilities and App Store metadata of your app in one place.
  • Application preferences that include no items users can set are instead shown in the About box.


New Features

  • Experimental HTTP/3 support can be enabled in Safari via Experimental Features in the Developer menu, and enabled system-wide using the Terminal command defaults write -g CFNetworkHTTP3Override -int 3. (62969220)


New Features

Safari and WebKit

New Features

  • Support for 4K HDR playback of YouTube videos. (64824895)
  • Support for Web Extensions is now available. Existing Chrome and Firefox extensions can be converted for Safari using xcrun safari-web-extension-converter and distributed through the App Store for use in Safari 14. (55707949)
  • Webpage Translation is now available in the U.S. and Canada. Supported languages include English, Spanish, Simplified Chinese, French, German, Russian, and Brazilian Portuguese. Safari will automatically detect if translation is available based on your Preferred Languages list. (64437861)


New Features

  • macOS Big Sur 11 beta improves system security by requiring an administrator password when a certificate trust settings change is made in the admin trust domain. Running as the root user alone is no longer sufficient to modify certificate trust. User trust domain settings continue to require confirmation by entering the password for the user’s account. This change may affect you if one of the following is true:
    • You have written scripts which call /usr/bin/security add-trusted-cert -d … as root.
    • Your process runs as root and calls the SecTrustSettingsSetTrustSettings function to trust a certificate.
  • Workflows that add trust settings in the admin trust domain, such as for an enterprise root certificate, may require modification if the user can’t authenticate as an administrator at the time settings are changed. (21855995)

Workaround: Use Apple Configurator 2 to create and install a configuration profile containing your root certificate.


Known Issues

  • ProgressView generic type signature has changed, adding the currentValueLabel generic parameter. This change doesn’t require any source changes, but it causes apps compiled using an earlier beta SDK to quit unexpectedly. (63580200)

Workaround: Re-compile apps for macOS Big Sur 11 Beta 6 or later to resolve this issue.

New Features

  • ToolbarItem attached to the content of a sheet will now display confirmationActioncancellationActiondestructiveAction and automatic placements below the the content of the sheet. (61180502)
  • ToolbarItem Label is now automatically used when the window’s toolbar is set to Icon and Text or Text Only. (67823018)
  • Adding a Spacer to a toolbar now creates flexible spaces. (64189289)
  • ToolbarItem now automatically creates an overflow menu item. (60104785)
  • Use the new .fileImporter() modifier to present a system interface for importing one or more files into your app, and the new .fileMover() modifier to move one or more existing files to a new location. The following is an example of a simple UI for importing and moving files:
  • struct FileMover : View { @Binding var selectedFiles: [URL]    var includeDirectories: Bool = false        @State private var isImporting: Bool = false    @State private var isMovingSelection: Bool = false

var body: some View {        List(selectedFiles, id: \.self) { url in            Text(url.absoluteString)        }        .toolbar {            Button(“Import”, action: { isImporting = true })            Button(“Move”, action: { isMovingSelection = true })        }        .fileImporter(            isPresented: $isImporting,            allowedContentTypes: includeDirectories ? [.item, .directory] : [.item],            allowsMultipleSelection: true        ) { result in            do {                selectedFiles = try result.get()            } catch {                // Handle failure.            }        }        .fileMover(isPresented: $isMovingSelection, files: selectedFiles) {            if case .success = $0 {                selectedFiles = []            } else {                // Handle failure.            }        }    }}

  • Use the new .fileExporter() modifier to present a system interface for exporting one or more documents from your app. In this example, an app provides a simple note-taking interface for quickly jotting down some text and then exporting it to disk:
  • struct QuickNote : View { @Binding var draft: QuickNoteDocument    @State private var isExporting: Bool = false
  • var body: some View {        TextEditor(text: $draft.text)            .toolbar {                Button(“Save”, action: { isExporting = true })            }            .fileExporter(                isPresented: $isExporting,                document: draft,                contentType: .plainText,                defaultFilename: “MyNote”            ) { result in                // Clear the draft now that it’s saved.                if case .success = result {                    text = “”                } else {                    // Handle failure.                }            }    }}
  • struct QuickNoteDocument : FileDocument { static var readableContentTypes: [UTType] { [.plainText] }
  • var text: String
  • init(text: String) {        text = text    }
  • init(configuration: ReadConfiguration) throws {        // Deserialize the document.    }

func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {        // Serialize the document.    }}

  • Use the new .fileMover() modifier to present a system interface for moving one or more existing files to a new location. (66182201)
  • The ImportFilesAction and ExportFilesAction APIs have been replaced with a collection of new view modifiers.
  • Color can be converted to and from CGColor. The ColorPicker can also now be configured with a binding to a CGColor. (56939085)
  • Introduced ToolbarItemGroup as a convenient way to place multiple items in a specific location of non-customizable toolbars. (64178863)
  • ProgressView now supports adding a secondary “current value label” that describes the current progress level of the task. Use the label to describe the overall task, and the currentValueLabel to provide more specific details about the progress of the task. (63580200)
  • FileDocument and have updated protocol requirements:
    • Their initializer requirement now has a single FileDocumentReadConfiguration parameter that the fileWrapper and contentType can be read from.
    • Their write() functions that were expected to write to an inout FileWrapper parameter are now fileWrapper() functions that return a FileWrapper instead.
    • The Document-based app templates in Xcode have been updated to reflect this change in API.
    • Source compatibility with the previous requirements will eventually be removed. (65146043)
  • Image is now redacted when the redacted(reason:) modifier is applied. (65047189)
  • InlinePickerStyle is now available and allows a Picker to appear in-line with the rest of the content in its surrounding container. The style will adapt its appearance for different containers and platforms, such as individual menu items in a menu. (59868844)
  • MenuPickerStyle is now available and allows a Picker to present its options within a menu. This style will display its options within a submenu when the Picker is nested within a MenuContextMenu, or CommandMenu. (65515392)
  • Using a TabView in a Settings scene will now use the correct style for macOS preference windows. The selected tab will be persisted if no selection binding is passed to the TabView. The window for a Settings scene will have an appropriate title by default. This will be either the name of the app followed by “Preferences”, or the label of the currently selected tab, if using TabView. (51558644)

Settings {    TabView {        Text(“General Settings”)            .tabItem {                Text(“General”)                Image(systemName: “gearshape”)            }        Text(“Advanced Settings”)            .tabItem {                Text(“Advanced”)                Image(systemName: “gearshape.2”)            }    }    .frame(width: 400, height: 400)}

  • NavigationView and HSplitView will now automatically separate their child panes’ toolbar items, aligning them with their associated split pane. (60105046)

NavigationView {    Sidebar()        .toolbar {            Button(action: {}) {                Label(“Sidebar Item”, systemImage: “plus”)            }        }    Detail()        .toolbar {            Button(action: {}) {                Label(“Detail Item”, systemImage: “square.and.pencil”)            }        }}

Third-Party Apps

Known Issues

  • You might experience kernel panics when using earlier versions of Parallels Desktop 16. (67358596)

Workaround: Upgrade to the most-recent version of Parallels Desktop 16.

  • Some third-party scripts might produce unexpected results due to the change in macOS version from 10.x to 11. (62477208)

Workaround: Set SYSTEM_VERSION_COMPAT=1 in the calling environment, for example: $ SYSTEM_VERSION_COMPAT=1

Time Machine

New Features

  • APFS-formatted backup volumes are now supported for faster, more compact, and more reliable backups. New local and network Time Machine backup destinations are formatted as APFS by default. Time Machine will continue backing up to existing HFS backup volumes. (65155545)


New Features

  • The Hypervisor framework now requires the entitlement. (63960391)
  • A new Virtualization framework provides high-level APIs to run Linux in a virtual machine. (64492914)



Known Issues

  • isPassLibraryAvailable() doesn’t ensure uniform availability of pass library functionality between platforms and devices. (60697880)

Workaround: Call a more specific API to check available functionality, such as canAddPasses().

New Features

  • Apple Pay support is now available to Mac Catalyst apps. Two methods have been added to existing delegate protocols. No changes are required for iPad apps, but one or both of these methods must be implemented when building for Catalyst. (64187739)
  • This method must be implemented to request a merchant session via your server, and return it via the handler. This mirrors the security model used in WebKit, and replaces listing merchant IDs in the app’s Apple Pay entitlements. This method in turn uses the following class to send back results:
  • API_AVAILABLE(macos(10.16), ios(14.0), watchos(7.0))@interface PKPaymentRequestMerchantSessionUpdate : NSObject
  • – (instancetype)initWithStatus:(PKPaymentAuthorizationStatus)status merchantSession:(nullable PKPaymentMerchantSession *)session;
  • @property (nonatomic, assign) PKPaymentAuthorizationStatus status;@property (nullable, nonatomic, strong) PKPaymentMerchantSession *session;



Known Issues

  • Legacy Xcode versions prior to 11.5 might unexpectedly quit when launched. (59991056)

Workaround: Run the following command in Terminal: defaults write DVTDisableMainThreadChecker 1, then deselect Main Thread Checker in the Diagnostic tab of the Run and Test actions for each scheme in your project.

New Features

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