Apple today seeded build 12F23 of OS X 10.8.5 to developers, offering a fifth version of the next Mac operating system update for testing. The release comes one week after the appearance of the previous beta of OS X 10.8.5, build 12F20.
NewImage
As with previous betas, the update comes with no known issues and can be downloaded via Apple's Developer Page or through the software update tool in the Mac App Store.

Testing on OS X 10.8.5 comes as Apple is also continuing work on its next major version of OS X, Mavericks. Apple has already seeded three developer previews of OS X Mavericks and has announced that it will launch the new operating system to the public this fall.

Top Rated Comments

macs4nw Avatar
162 months ago
The regularity of these ML seeds is reassuring, considering all the work that must be going on with iOS7 and Mavericks.
Score: 5 Votes (Like | Disagree)
nikicampos Avatar
162 months ago
I guess this will be the last update for Mountain Lion, good.

Since Snow Leopard I think OS X is not that at it's best, hopefully Mavericks will be more like Snow Leopard performance wise.
Score: 5 Votes (Like | Disagree)
dastinger Avatar
162 months ago
And why would all that come to OSX with an incremental update of an OS that will be outdated by fall?

Do you know what they will probably fail on doing? Blocking people from posting entire replies using hugely sized bold fonts on forums.
Score: 4 Votes (Like | Disagree)
Parasprite Avatar
162 months ago
I guess this will be the last update for Mountain Lion, good.

What makes you say that? Granted these aren't the days where we'd see 10.x.13, but I don't see why anything would prove us failing to see 10.8.6 in the future.
Score: 4 Votes (Like | Disagree)
RayK Avatar
162 months ago
Hopefully if this is the last version of 10.8 they release all of the new hardware BEFORE this so I don't have to support yet another OS so soon... BRING ON THE HASWELL HARDWARE!
Score: 3 Votes (Like | Disagree)
Mr. Wonderful Avatar
162 months ago
I love how people don't remember anymore how buggy and graphically slow Snow Leopard was until 10.6.4 or 10.6.5...

If you want refinement of stability, yearly major releases of an OS are not what you're looking for.
Score: 2 Votes (Like | Disagree)

Popular Stories

top stories 2025 12 20

Top Stories: iOS 26.3 Beta, Major Apple Leaks, and More

Saturday December 20, 2025 6:00 am PST by
You'd think things would be slowing down heading into the holidays, but this week saw a whirlwind of Apple leaks and rumors while Apple started its next cycle of betas following last week's release of iOS 26.2 and related updates. This week also saw the release of a new Apple Music integration with ChatGPT, so read on below for all the details on this week's biggest stories! Top Stories i...
maxresdefault

Where's the New Apple TV?

Monday December 22, 2025 11:30 am PST by
Apple hasn't updated the Apple TV 4K since 2022, and 2025 was supposed to be the year that we got a refresh. There were rumors suggesting Apple would release the new Apple TV before the end of 2025, but it looks like that's not going to happen now. Subscribe to the MacRumors YouTube channel for more videos. Bloomberg's Mark Gurman said several times across 2024 and 2025 that Apple would...
iPhone Top Left Hole Punch Face ID Feature Purple

iPhone 18 Pro Features Leaked in New Report, Including Under-Screen Face ID

Tuesday December 16, 2025 8:44 am PST by
Next year's iPhone 18 Pro and iPhone 18 Pro Max will be equipped with under-screen Face ID, and the front camera will be moved to the top-left corner of the screen, according to a new report from The Information's Wayne Ma and Qianer Liu. As a result of these changes, the report said the iPhone 18 Pro models will not have a pill-shaped Dynamic Island cutout at the top of the screen....
ios 18 security update

Don't Want to Upgrade to iOS 26? Here's How to Stay on iOS 18 [Update: Now Unavailable]

Friday December 19, 2025 10:37 am PST by
Since the beginning of December, Apple has been pushing iPhone users who opted to stay on iOS 18 to install iOS 26 instead. Apple started by making the iOS 18 upgrades less visible, and has now transitioned to making new iOS 18 updates unavailable on any device capable of running iOS 26. If you have an iPhone 11 or later, Apple is no longer offering new versions of iOS 18, even though there...
iPhone Chips

Apple Clings to Samsung as RAM Prices Soar

Monday December 22, 2025 6:17 am PST by
Apple is significantly increasing its reliance on Samsung for iPhone memory as component prices surge, according to The Korea Economic Daily. Apple is said to be expanding the share of iPhone memory it sources from Samsung due to rapidly rising memory prices. The shift is expected to result in Samsung supplying roughly 60% to 70% of the low-power DRAM used in the iPhone 17, compared with a...
apple beta 26 lineup

Apple's 2026 and 2027 Product Roadmap: Foldable iPhone, iPhone 18 Pro, M5 Macs, and More

Tuesday December 16, 2025 4:42 pm PST by
There has been a whirlwind of rumors over the last few days, sourced from leaked internal software designed for the iPhone and the Mac, and news sites like The Information. Below, we have a quick recap of everything we've heard this week, which serves as a guide to Apple's product plans in 2026 and beyond. We've organized the info by likely release date, though there are some products that...
generic tracking prompt orange

Apple Hit With Supersized Fine in Italy Over an iPhone Privacy Feature

Monday December 22, 2025 7:47 am PST by
Italy's Competition Authority (AGCM) has imposed a €98.6 million ($116 million) fine on Apple over its App Tracking Transparency feature. Since the release of iOS 14.5 in April 2021, Apple has required apps to ask for permission before tracking a user's activity across other apps and websites for personalized advertising, as part of a feature named App Tracking Transparency. If a user...