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
164 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
164 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
164 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And why would all that come to OSX with an incremental update of an OS that will be outdated by fall?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
164 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
164 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
164 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

Aston Martin CarPlay Ultra Screen

Apple's CarPlay Ultra to Expand to These Vehicle Brands Later This Year

Sunday February 1, 2026 10:08 am PST by
Last year, Apple launched CarPlay Ultra, the long-awaited next-generation version of its CarPlay software system for vehicles. Nearly nine months later, CarPlay Ultra is still limited to Aston Martin's latest luxury vehicles, but that should change fairly soon. In May 2025, Apple said many other vehicle brands planned to offer CarPlay Ultra, including Hyundai, Kia, and Genesis. In his Powe...
Apple Logo Black

Apple's Next Launch is 'Imminent'

Sunday February 1, 2026 12:31 pm PST by
The calendar has turned to February, and a new report indicates that Apple's next product launch is "imminent," in the form of new MacBook Pro models. "All signs point to an imminent launch of next-generation MacBook Pros that retain the current form factor but deliver faster chips," Bloomberg's Mark Gurman said on Sunday. "I'm told the new models — code-named J714 and J716 — are slated...
Apple MacBook Pro M4 hero

New MacBook Pros Reportedly Launching Alongside macOS 26.3

Sunday February 1, 2026 5:42 am PST by
Apple is planning to launch new MacBook Pro models with M5 Pro and M5 Max chips alongside macOS 26.3, according to Bloomberg's Mark Gurman. "Apple's faster MacBook Pros are planned for the macOS 26.3 release cycle," wrote Gurman, in his Power On newsletter today. "I'm told the new models — code-named J714 and J716 — are slated for the macOS 26.3 software cycle, which runs from...
iOS 26

iOS 26.3 and iOS 26.4 Will Add These New Features to Your iPhone

Tuesday February 3, 2026 7:47 am PST by
We are still waiting for the iOS 26.3 Release Candidate to come out, so the first iOS 26.4 beta is likely still at least a week or two away. Following beta testing, iOS 26.4 will likely be released to the general public in March or April. Below, we have recapped known or rumored iOS 26.3 and iOS 26.4 features so far. iOS 26.3 iPhone to Android Transfer Tool iOS 26.3 makes it easier...
14 inch MacBook Pro Keyboard

Apple Changes How You Order a Mac

Saturday January 31, 2026 10:51 am PST by
Apple recently updated its online store with a new ordering process for Macs, including the MacBook Air, MacBook Pro, iMac, Mac mini, Mac Studio, and Mac Pro. There used to be a handful of standard configurations available for each Mac, but now you must configure a Mac entirely from scratch on a feature-by-feature basis. In other words, ordering a new Mac now works much like ordering an...