Apple today seeded the fourth beta of an upcoming macOS Sierra 10.12.3 update to developers, a few days after seeding the third 10.12.3 beta and more than a month after releasing macOS Sierra 10.12.2, the second update to the macOS Sierra operating system.

The macOS Sierra 10.12.3 update is available for download through the Apple Developer Center or through the software update mechanism in the Mac App Store.

macos-10-12-3-beta
According to Apple's release notes, the 10.12.3 update "improves the stability, compatibility, and security of your Mac." No specific changes, bug fixes, or feature additions were discovered in the first three betas, but we'll update this post should any new features be found in the fourth beta.

With bug fixes, it's often hard to determine exactly what's included in an update until Apple supplies detailed release notes with a release. We do, however, know that this update fixes a Safari bug that caused battery life problems during the MacBook Pro testing conducted by Consumer Reports.

Available since September, macOS Sierra is the latest Mac operating system. It includes Siri support, Apple Pay for the web, Universal Clipboard, Apple Watch auto unlocking, improved iCloud Drive integration, Picture-in-Picture multitasking, and dozens of smaller features that can be found in our macOS Sierra roundup.

Update: The fourth macOS Sierra 10.12.3 beta is also available for public beta testers.

Related Forum: macOS Sierra

Top Rated Comments

hippielover Avatar
115 months ago
Does anyone know what has been changed since beta 2 and 3
I got fatter
Score: 23 Votes (Like | Disagree)
Vashetti Avatar
115 months ago
Public Beta too
Score: 3 Votes (Like | Disagree)
MacBird Avatar
115 months ago
Build 16D30a
Score: 2 Votes (Like | Disagree)
jlc1978 Avatar
115 months ago
i wonder if they fixed the USB bug where drives are disconnected and not recognized after waking from sleep...
Score: 2 Votes (Like | Disagree)
ghostface147 Avatar
115 months ago
Hmmm, that damn iTunes sync bug needs to be fixed.
Score: 1 Votes (Like | Disagree)
Vashetti Avatar
115 months ago
I learned from Apple employee that installing beta leaves some junk on the phone that cannot be removed unless you setup phone as new. Some of the issues that I experienced includes (1) super slow "copying diagnostics", (2) local video not syncing with TV app, and (3) ballooning iCloud backup size.

Needless to say, I shan't bother with iOS beta anymore.
Great. But what does that have to do with macOS?
Score: 1 Votes (Like | Disagree)

Popular Stories

ios 26 1 slide to stop

iOS 26.1 Brings Back 2007 Feature in New Way

Friday October 31, 2025 1:40 pm PDT by
The upcoming iOS 26.1 update includes a small but helpful change for iPhones, and it could prevent you from running late to something important. Specifically, when an alarm goes off in the Clock app, there is a new "slide to stop" control on the screen for turning off the alarm. On previous iOS 26 versions, there is simply a large "stop" button, which could be accidentally tapped. The new ...
M5 MacBook Pro

Waiting for New Macs? Apple Just Shared Bad News

Friday October 31, 2025 7:32 am PDT by
Apple has just given a strong indication that it will not be releasing any additional new Macs for the remainder of the year. Apple's CFO Kevan Parekh dropped the hint during the company's earnings call on Thursday:On Mac, keep in mind, we expect to face a very difficult compare against the M4 MacBook Pro, Mac mini, and iMac launches in the year-ago quarter.Parekh essentially gave a heads up ...
iPhone 17 Pro Cosmic Orange

8 Reasons to Wait for Next Year's iPhone 18 Pro

Thursday October 30, 2025 4:42 am PDT by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models at the same time, which is why we often get rumored features months ahead of launch. The iPhone 18 series is no different, and we already have a good idea of what to expect for the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth...
iOS 26

6 New Things Your iPhone Can Do in iOS 26.1

Wednesday October 29, 2025 4:22 am PDT by
Apple is about to drop iOS 26.1, the first major point release since iOS 26 was rolled out in September, and there are at least six notable changes and improvements to look forward to. We've rounded them up below. Apple has already provided developers and public beta testers with the release candidate version of iOS 26.1, which means Apple will likely roll out the update to all compatible...
Coffee Burgundy and Purple iPhone 18 Pro Mock 1

Leaker Outlines Potential New Colors for iPhone 18 Pro

Friday October 31, 2025 8:28 am PDT by
Apple's iPhone 18 Pro models could be available in new rich and warm color option, according to a known leaker. The Weibo user known as "Instant Digital" today suggested that next-year's iPhone 18 Pro models will be available in at least one of the following color options: Coffee, purple, and burgundy. The iPhone XR, iPhone 11, iPhone 12, iPhone 14, and iPhone 14 Pro were all available in ...
Apple Foldable Thumb

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Friday October 31, 2025 8:52 am PDT by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Below, we've collated an updated set of key details that have been leaked about Apple's foldable iPhone so far. Ove...
apple tv hd

Apple Launched Its Big New Vision for TV 10 Years Ago Today

Thursday October 30, 2025 8:58 am PDT by
Apple launched the Apple TV HD, the Siri Remote, tvOS, and their accompanying App Store a decade ago today, marking a major overhaul of the device. The new vision for the Apple TV was unveiled on September 9, 2015 during Apple's "Hey Siri" event in San Francisco, where CEO Tim Cook introduced the device with the statement, "The future of TV is apps." The announcement represented a major...
iOS 26

Apple This November: iOS 26.2 Beta, Rumored New Products, and More

Thursday October 30, 2025 12:42 pm PDT by
Tomorrow is Halloween, and then November is upon us. Below, we outline what to expect from Apple next month, as the slower holiday season approaches. Apple is expected to kick off November by releasing iOS 26.1, iPadOS 26.1, macOS 26.1, watchOS 26.1, tvOS 26.1, and visionOS 26.1. With beta testing now wrapped up, the updates will likely be released this Monday, November 3 or Tuesday,...
iOS 26

iOS 26.1 Coming Soon: New Features for Your iPhone and Release Date

Monday October 27, 2025 7:55 am PDT by
The upcoming iOS 26.1 update includes a handful of new features and changes for iPhones, including a toggle for changing the appearance of the Liquid Glass design, "slide to stop" for alarms in the Clock app, and more. Below, we outline key details about iOS 26.1. Release Date Given that Apple has yet to seed an iOS 26.1 Release Candidate, which is typically the final beta version, the...
iOS 18 Siri Personal Context

Apple CEO Tim Cook Says Revamped Siri on Track to Launch Next Year

Thursday October 30, 2025 1:50 pm PDT by
Apple CEO Tim Cook today said that a more personalized version of Siri remains on track to launch at some point next year, with the new set of features expected to debut on the iPhone as part of iOS 26.4 in March or April. "We're also excited for a more personalized Siri," said Cook, on Apple's earnings call for the third quarter of the 2025 calendar year. "We're making good progress on it,...