Apple Seeds Fourth macOS Sierra 10.12.1 Beta to Developers and Public Beta Testers

Apple today seeded the fourth beta of an upcoming macOS Sierra update to developers and public beta testers for testing purposes, one week after seeding the third beta and three weeks after releasing the new macOS Sierra operating system to the public.

macOS Sierra 10.12.1 beta 4 can be downloaded from the Apple Developer Center or through the Software update mechanism in the Mac App Store for those who already have an earlier 10.12.1 beta installed.

macossierra
macOS Sierra 10.12.1 appears to focus on bug fixes and under-the-hood performance improvements to address issues that have been found since the operating system's release, and it's also likely adding features designed for next-generation MacBook Pro models set to be released later this year.

Few outward-facing changes were discovered in the first three betas, but it does include Photos support for the new iPhone 7 Plus Portrait feature introduced with iOS 10.1. New features discovered in the fourth 10.12.1 beta will be listed below.

macOS Sierra is a significant update that brings features like Siri support, a new storage optimization option, cross device copy paste, auto unlocking with the Apple Watch, and more. For full details on macOS Sierra, make sure to check out our roundup.

Related Forum: macOS Sierra

Popular Stories

iOS 26

15 New Things Your iPhone Can Do in iOS 26.2

Friday December 5, 2025 9:40 am PST by
Apple is about to release iOS 26.2, the second major point update for iPhones since iOS 26 was rolled out in September, and there are at least 15 notable changes and improvements worth checking out. We've rounded them up below. Apple is expected to roll out iOS 26.2 to compatible devices sometime between December 8 and December 16. When the update drops, you can check Apple's servers for the ...
ios 18 to ios 26 upgrade

Apple Pushes iPhone Users Still on iOS 18 to Upgrade to iOS 26

Tuesday December 2, 2025 11:09 am PST by
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent. Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
iOS 26

Apple Seeds iOS 26.2 and iPadOS 26.2 Release Candidates to Developers and Public Beta Testers

Wednesday December 3, 2025 10:33 am PST by
Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....
Photos App Icon Liquid Glass

John Gruber Shares Scathing Commentary About Apple's Departing Software Design Chief

Thursday December 4, 2025 9:30 am PST by
In a statement shared with Bloomberg on Wednesday, Apple confirmed that its software design chief Alan Dye will be leaving. Apple said Dye will be succeeded by Stephen Lemay, who has been a software designer at the company since 1999. Meta CEO Mark Zuckerberg announced that Dye will lead a new creative studio within the company's AR/VR division Reality Labs. On his blog Daring Fireball,...
Intel Inside iPhone Feature

Apple's Return to Intel Rumored to Extend to iPhone

Friday December 5, 2025 10:08 am PST by
Intel is expected to begin supplying some Mac and iPad chips in a few years, and the latest rumor claims the partnership might extend to the iPhone. In a research note with investment firm GF Securities this week, obtained by MacRumors, analyst Jeff Pu said he and his colleagues "now expect" Intel to reach a supply deal with Apple for at least some non-pro iPhone chips starting in 2028....
iOS 26

When Will Apple Release iOS 26.2?

Monday December 1, 2025 4:37 pm PST by
We're getting closer to the launch of the final major iOS update of the year, with Apple set to release iOS 26.2 in December. We've had three betas so far and are expecting a fourth beta or a release candidate this week, so a launch could follow as soon as next week. Past Launch Dates Apple's past iOS x.2 updates from the last few years have all happened right around the middle of the...
maxresdefault

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

Monday December 1, 2025 3:00 am PST 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. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
ive and altman

Jony Ive's OpenAI Device Barred From Using 'io' Name

Friday December 5, 2025 6:22 am PST by
A U.S. appeals court has upheld a temporary restraining order that prevents OpenAI and Jony Ive's new hardware venture from using the name "io" for products similar to those planned by AI audio startup iyO, Bloomberg Law reports. iyO sued OpenAI earlier this year after the latter announced its partnership with Ive's new firm, arguing that OpenAI's planned "io" branding was too close to its...
iphone air camera

iPhone Air's Resale Value Has Dropped Dramatically, Data Shows

Thursday December 4, 2025 5:27 am PST by
The iPhone Air has recorded the steepest early resale value drop of any iPhone model in years, with new data showing that several configurations have lost almost 50% of their value within ten weeks of launch. According to a ten-week analysis published by SellCell, Apple's latest lineup is showing a pronounced split in resale performance between the iPhone 17 models and the iPhone Air....
iPhone 17 Pro Cosmic Orange

iPhone 17 Pro Lost a Camera Feature Pro Models Have Had Since 2020

Thursday December 4, 2025 5:18 am PST by
iPhone 17 Pro models, it turns out, can't take photos in Night mode when Portrait mode is selected in the Camera app – a capability that's been available on Apple's Pro devices since the iPhone 12 Pro in 2020. If you're an iPhone 17 Pro or iPhone 17 Pro Max owner, try it for yourself: Open the Camera app with Photo selected in the carousel, then cover the rear lenses with your hand to...

Top Rated Comments

Jeremy1026 Avatar
120 months ago


macOS Sierra is a significant update that brings features like Siri support, a new storage optimization option, cross device copy paste, auto unlocking with the Apple Watch, and more. For full details on macOS Sierra, make sure to check out our roundup ('https://www.macrumors.com/roundup/macos-sierra/').
We get it.
Score: 25 Votes (Like | Disagree)
edgonzalez32 Avatar
120 months ago
Remember when Apple used to make computers? So sad those days have passed. Been waiting a year for an updated MBP and will probably have to give up and buy a PC instead. Sad tears.
I mean, just wait a couple weeks. How bad do you need one? And why does it seem like everyone here needs a new Mac every 3 years? My 2007 MBP lasted all the way until 2013. I'm now using a 2013 rMBP, everything maxed out and I don't see myself buying a new Mac until at least 2020. What else could I possibly need?
Score: 17 Votes (Like | Disagree)
jmh600cbr Avatar
120 months ago
BRING ON THE MACS
Score: 9 Votes (Like | Disagree)
SamVilde Avatar
120 months ago
I mean, just wait a couple weeks. How bad do you need one? And why does it seem like everyone here needs a new Mac every 3 years? My 2007 MBP lasted all the way until 2013..
Oh, so you know exactly what it's like to be sitting here with an awesome much-loved 2008 MacBook, with its outdated and degraded screen, replacement battery barely able to hold an hour charge, refreshing the MacRumors feed because there's no way we're paying full price on an already-outdated upgrade a month before the launch of something better, and because after 8 years we really do deserve an improved machine in exchange for our frugality and patience. You know what it's like to be in this position.

How badly do I need one? I can wait a few weeks. I can wait a few months if I have to. But I don't feel like I'm being pathetic in wanting a replacement.
Score: 7 Votes (Like | Disagree)
ipodlover77 Avatar
120 months ago
Any hints towards the new macs?
Score: 7 Votes (Like | Disagree)
32828870 Avatar
120 months ago
Interesting to see if Siri will handle HomeKit...

...and new Mac's? Maybe? No? Prada Watchbands?

Score: 6 Votes (Like | Disagree)