Apple (release notes, security, enterprise, developer, full installer, IPSW):

Explore what’s new for macOS 27.

The page is designed in an annoying way that requires sideways scrolling, and there doesn’t seem to be a PDF list of the new features like in previous years.

See also:

• Jason Snell
• Juli Clover
• Marcus Mendes
• William Gallagher
• Mr. Macintosh
• Reddit

Jeff Johnson:

There’s also a DEPRECATION NOTICE at the top of the man page that lists the diskutil replacements for hdiutil subcommands.

Patrick Wardle:

Fixed: launchd no longer supports loading launchd property list files with the quarantine extended attribute.

Dave Nanian:

[Even] though a bootable backup is properly configured to boot, they aren’t showing up as choices in either the startup disk preference pane or the startup picker. (FB24210103, reported quite a while ago, Apple friends.)

Previously:

• Golden Gate Release Candidate
• Preparing to Update to Golden Gate
• macOS 27 Public Beta
• Glow Leopard
• macOS 27 Golden Gate Announced
• macOS Tahoe 26

Update (2026-09-17): See also: Hacker News.

Andrew Cunningham (Hacker News):

Generative AI is unavoidable if you install macOS 27 Golden Gate. I’m being very literal: There used to be a toggle you could hit if you wanted to turn off Apple Intelligence and delete the gigabytes’ worth of AI models it would download to your disk, and now there isn’t. Apple Intelligence defines the Golden Gate release, in everything from its marketing to its features to the chips it runs on to the amount of space it takes on your disk.

[…]

More impressively, for apps that support it, the iPhone Mirroring window can now be resized dynamically while running apps. Apps will resize themselves to take up all the available space, and once the window is wide enough, you can even take advantage of multi-column iPad-style views for the apps that offer them.

[…]

For most Mac users, though, Golden Gate is a no-brainer update with few major downsides. It won’t hurt anything to wait until the 27.1 or 27.2 release if you’re already on macOS 15 Sequoia or macOS 26 Tahoe and you’re not in a hurry.

Juli Clover:

macOS Golden Gate: 10 Features to Try First

Paul Haddad:

Did Virtualization under 27 get hit with the slow stick? Trying to run a Mac VM on my M1 Ultra and it feels basically unusable. Getting Intel flashbacks.

Jeff Johnson:

In System Settings Privacy & Security, the Accessibility pane has been renamed to Device Control and Data Access.

Avi Drissman:

Have you been noticing that, starting with macOS 27, you have been consistently failing to SSH to a remote machine? Is it the case that the remote machine’s password ends with a shifted character?

There is a new setting: “Shift Return sends Meta Return” under Settings > Profiles > (profile) > Keyboard. This setting (enabled by default!) will cause a shift-return keypress to insert an ESC before the return is sent.

Rich Trouton:

As part of testing macOS Golden Gate, it was discovered by myself and others that MDM enrollment does not appear to completely work.

Adam Maxwell (tweet):

Golden Gate broke AuthorizationExecuteWithPrivileges such that spawned tasks no longer inherit PATH of the calling process[…]

Daniel Compton:

After upgrading to macOS 27 Golden Gate, my beloved copy of 1Password 7 started crashing every time I unlocked it.

[…]

If you’re planning ahead, you can disable Watchtower from Settings before you upgrade to macOS 27, but if you’ve already upgraded, then you’ll need to disable it with the following terminal command[…]

Update (2026-09-21): Benjamin Mayo:

Ever since updating to Golden Gate, my Mac now periodically makes a scratchy paper alert sound. No idea from what.

Chris Pepper:

Hopefully 1Password will upgrade v7 for OS 27 compatibility, but I can’t count on them fixing bugs in v7 — they’re pushing users to v8.

I found a ‘fix’ for this crash, but that command didn’t work (even after enabling Full Disk Access for Terminal so it could actually execute), and isn’t available on iPhone or iPad.

Nicholas Riley:

Golden Gate status: wow, the new menu extra/Control Center area is rough. Not just unpolished UI behaviors but multiple crashes. Hidden Bar is no longer functional and none of the replacements I found actually worked, while having about 100 features I don’t want.

System keyboard shortcuts also seem to be an area that weren’t well tested. My preferred screenshot shortcuts were ignored until I opened that section of System Settings, and some Siri thing created a conflict with Spotlight so I get both of them when I press ⇧⌘Space.

Previously:

• Golden Gate Liquid Glass

Update (2026-09-23): Jesse Squires:

macOS golden gate is still shockingly terrible in unexpected ways.

Steve Troughton-Smith:

I’m no math expert, but I’m pretty sure this doesn’t add up to anywhere near 16GB. I’ve only started seeing this dialog in the release build of macOS 27.0, despite running the betas all summer, so clearly there are some ghosts in this build

Mario Guzmán:

Okay… how do you

1. make everything super huge like the text and pictures… while
2. having way more empty space than you need AND STILL have to
3. truncate your text labels?

8 of the 9 text labels are truncated.

Can we please have designers who know how to design for DESKTOP software and NOT magazines/print?

Jeff Johnson:

There are a surprising number of behavioral bugs in Golden Gate. It's not just a superficial update. Apple is basically breaking AppKit.

Mark Lilback:

I reported a bug to Apple in May, found while building Alcove. Two OS releases later it still isn’t fixed. It has gotten worse with each one.

[…]

On the betas the whole window went blank after the Cmd-Tab: sidebar, content, detail pane, status bar, everything but the toolbar. On the 27.0 release it usually doesn’t wait for the Cmd-Tab. In 5 of 6 clean launches the window came up with only the toolbar drawn. Cmd-Tabbing away and back doesn’t fix it. It moves the sidebar’s first row up under the traffic-light buttons and leaves the rest of the window empty[…]

Jeff Johnson (Reddit):

Golden Gate Finder bug:

If you start dragging a file, the mouse scroll wheel stops working.

Jeff Johnson:

I’m seeing a bug on Golden Gate where main menu item titles are not displayed if the item is added to the menu after launch. Examples: the Safari Develop menu and the Profile menus of Chrome and Firefox.

Update (2026-09-24): Avi Drissman:

It’s bizarre that hiding a main menu item would hold the space rather then shift things over.

Jeff Johnson:

Search on Golden Gate is twice as good.

Update (2026-09-25): Ric Ford:

Randy Singer emailed us about printer and scanner failures following macOS 27 installation. Fortunately, there’s a fix: reinstalling Apple’s deprecated and removed Rosetta 2 emulation code[…]

Paul Kafasis:

We’re also already recommending upgrading your Mac to Golden Gate. The new OS includes several important audio improvements, and as a result, Golden Gate provides the best experience when using our apps. Below, you’ll find details on key bug fixes Apple included in MacOS 27.

pdfu (via Jeff Johnson):

Hidden behind a feature flag, the System Settings app can now be resized in any direction. You can make the app window narrower than the default too, or adjust the sidebar to get even more space.

Update (2026-09-28): Matt:

Steve Jobs would fire the entire company and replace them with AI if he was alive to see this

Collin Allen:

Turns out, Backblaze is half busted on macOS 27 and there’s no fix yet. Have to launch /Library/Backblaze.bzpkg/bzbmenu.app manually for now, it seems.

Update (2026-10-05): Karsten Kusche:

Kudos to 1Password for providing an update for version 7 on iOS and macOS to restore compatibility with this year’s operating systems!!

Apple:

In macOS 28 and later, the Mac OS Extended file system format will be supported only for volumes (disks and other storage devices) that aren’t encrypted. For future macOS compatibility, either decrypt or reformat any encrypted Mac OS Extended volumes.

I think Apple removed the user interface for creating such volumes way back in Big Sur. It’s not really surprising that they’re going away, although only offering a year of warnings seems rather aggressive. Many people delay updating to major OS versions or wait until they get a new Mac. There will be users that switch to a Mac that can only run macOS 28 and get rid of their old one before realizing that some drive they haven’t connected in a while won’t mount.

The other surprising part is that Apple’s options—reformat or decrypt—are not great. During the initial transition to APFS, macOS would transparently convert an encrypted HFS+ boot volume to encrypted APFS without rewriting any data. This functionality is nominally still available via the diskutil apfs convert command, but Apple hasn’t mentioned this or built an automatic upgrader GUI.

[Decrypting] doesn’t apply to encrypted Time Machine backup disks.

It’s obvious why. The old Time Machine format with hard links is totally different from the new one based on APFS snapshots. But this means that you’ll either need to buy a new Time Machine drive for use with macOS 28 or delete your backup history. Even if you keep the old drive, you’ll need an older boot drive or an old Mac in order to be able to access it.

Previously:

• Searching Time Machine Backups and Versions
• macOS 27 Golden Gate Announced
• macOS 27 to Drop Support for AirPort and Time Capsule Backups
• Removing Unwanted APFS Time Machine Backups
• Should You Continue Using HFS+?
• Time Machine Evolution and APFS
• SuperDuper 3.3 for Catalina
• APFS to be Mandatory for SSDs in High Sierra

Update (2026-07-24): Marcus Mendes:

Apple has now revised the page to add a third option, allowing users to convert an encrypted HFS+ volume directly to encrypted APFS without decrypting it first.

[…]

The company has also removed its previous instructions for decrypting the volume first, converting it to APFS without erasing it, and then optionally re-encrypting it.

Hammer:

Ignore Apple’s guidance and do not use Convert to APFS in Disk Utility for disk images.

The first encrypted HFS+ disk image I tried to convert that way failed and left me with an unusable disk image. If I didn’t have backups I’d have lost its contents.

It didn’t corrupt the disk images that I tried, but it didn’t work, either, instead failing with an error about expecting a GPT partitioning scheme.

Update (2026-07-28): Howard Oakley:

As encrypted disk images have never used CoreStorage, withdrawal of support for that has no impact on the continued use of any form of encrypted disk image, including those using HFS+ as their virtual file system.

This is a good point. Apple’s support page refers to “encrypted Mac OS Extended disks,” but the developer release notes refer to CoreStorage specifically. So this shouldn’t affect most encrypted disk images, which show up in Finder as unencrypted after mounting. The encryption is at the disk image level rather than at the file system level. However, I’m not sure that all encrypted disk images are safe. Presumably, a device image, which directly copies the blocks rather than the files, would still use CoreStorage.

Erik Schamper:

ASIF takes a lot of inspiration from existing virtual disk formats. Practically, that means it’s another sparse virtual disk format, and functions very similar to sparse VMDK, VHDX or QCOW2 files (for the uninitiated, it allow you to store a large disk, or file, in a smaller, “sparse” manner).

Shortly before the release of macOS Tahoe (late 2025), I thought it’d be a fun exercise to try and write a parser for ASIF files.

Previously:

• DropDMG 3.7
• ASIF Disk Images in macOS Tahoe