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

Apple today seeded the fifth beta of an upcoming macOS Sierra update to developers and public beta testers, just over one week after seeding the fourth beta and a month after releasing the new macOS Sierra operating system to the public.

macOS Sierra 10.12.1 beta 5 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.

sierra10121beta
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 four betas, but it 10.12.1 does include Photos support for the new iPhone 7 Plus Portrait feature introduced with iOS 10.1. New features discovered in the fifth 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

iPhone 17 Pro 3 4ths Perspective Aluminum Camera Module 1

New iPhone 17 Pro Details: Brighter Display, Best Battery Life, and More

Wednesday September 3, 2025 5:33 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max models will feature a number of significant display, thermal, and battery improvements, according to new late-stage rumors. According to the Weibo leaker known as "Instant Digital," the iPhone 17 Pro models will feature displays with higher brightness, making it more suitable for use in direct sunlight for prolonged periods. The iPhone 16 Pro and...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 Pro Clear Case Leak Reveals Three Key Changes

Sunday August 31, 2025 1:26 pm PDT by
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface. The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas. Image Credit: @MajinBuOfficial The images show three alleged changes compared to Apple's iP...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 and iPhone 17 Pro Prices Estimated Ahead of Apple Event Next Week

Tuesday September 2, 2025 1:50 pm PDT by
Just one week before Apple is expected to unveil the iPhone 17 series, an analyst has shared new price estimates for the devices. Here are J.P. Morgan analyst Samik Chatterjee's price estimates for the iPhone 17 series in the United States, according to 9to5Mac: Model Starting Price Model Starting Price Change iPhone 16 $799 iPhone 17 ...
iphone 16 pro ghost hand

iPhone 17 Pro: 5 Reasons Not to Upgrade This Year

Monday September 1, 2025 4:35 am PDT by
Apple will launch its new iPhone 17 series this month, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive. If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming to...
iPhone 17 Pro Dark Blue and Orange

iPhone 17 Release Date, Pre-Orders, and What to Expect

Thursday August 28, 2025 4:08 am PDT by
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall. At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
Apple Watch Ultra 2 Complications

Apple Watch Ultra 3 Coming Next Week: Eight Reasons to Upgrade

Thursday September 4, 2025 7:38 am PDT by
We're only days away from Apple's "Awe dropping" fall event scheduled to take place on Tuesday, September 9 – and along with the new iPhone 17 series, we're going to get a new version of the Apple Watch Ultra for the first time since 2023. By the time the Ultra 3 is unveiled, it will have been two years since the previous model arrived. The intervening period has left plenty of room for...

Top Rated Comments

Dydegu Avatar
116 months ago


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 ('https://www.macrumors.com/2016/09/28/late-october-macbook-pro/') set to be released later this year.
Don't even give them the option. Change that to next week.
Score: 9 Votes (Like | Disagree)
otternonsense Avatar
116 months ago
I hope they've fixed all the Safari bugs and glitches.
Score: 7 Votes (Like | Disagree)
0958400 Avatar
116 months ago
For the love of god please fix the issue with external 4K monitors (Dell P2415Q in my case) not turning on when connected to a closed rMBP on a restart and then not allowing the built in screen to turn on when opening it, causing a hard reboot with the screen open. Worked great in all versions of El Capitan..
Absolutely agree. Asus here, same problem.
And not just that:

* flickering screen,
* buggy video controls,
* sudden resets,
* BEACHBALLS,
* software that stopped for working (for no apparent reason),
* slow behaviour,
* iTunes before that was way snappier (don't get me started on the stupid hearts-system where one state cannot be accessed in playlists).
* iTunes Backups from iPhone cannot be saved "no disk space" (with 230GB available),
* Word cannot save temporary files anymore - and crashes,
* Bluetooth automatically disconnects - reconnects - disconnects.
* Cannot use the Apple Watch to unlock, as I have several iPads, including an old one which will stop working once I activate two-way authentification...
* losing WiFi
* Safari cannot open webpages (Firefox can)
* Lightroom crashes when converting to DNG


... all of this worked with Mavericks and stopped with Sierra. Thank you, Apple.

The list is so long, I have regretted updating my system and I will certainly never ever again update my computer, once the last service update has come along.
Sierra has been a disappointment all along.

Phew...

Has Apple forgotten that people actually work with this OS and depend on its reliability. Have they forgotten that this was the reason we chose to invest money?

I love Apple. I hate what it has become.
Score: 7 Votes (Like | Disagree)
meaning-matters Avatar
116 months ago
Picture doesn't look like invitation; not interested.
Score: 5 Votes (Like | Disagree)
justperry Avatar
116 months ago
My ipad is not finding the update. I got Beta 4 the other day but it says up to date now. I even restarted it. Did the ipad not get Beta 5?
Haha, this is MacOS.:p
Score: 4 Votes (Like | Disagree)
CheesePuff Avatar
116 months ago
For the love of god please fix the issue with external 4K monitors (Dell P2415Q in my case) not turning on when connected to a closed rMBP on a restart and then not allowing the built in screen to turn on when opening it, causing a hard reboot with the screen open. Worked great in all versions of El Capitan..
Score: 4 Votes (Like | Disagree)