Apple today seeded build 12F17 of OS X 10.8.5 to developers, offering a third 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 12F13.

12f17
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 two 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

WildCowboy Avatar
161 months ago
Can any one explain to me why they are still doing this instead of putting extra work in Mavericks? Not that it bothers me, just asking

Mavericks isn't coming for months, and there are things in Mountain Lion that need fixing.
Score: 14 Votes (Like | Disagree)
beelzebubba Avatar
161 months ago
Can any one explain to me why they are still doing this instead of putting extra work in Mavericks? Not that it bothers me, just asking

Because many people still run ML and will even after Mavericks comes out. ML will likely be the end of the line for some older Macs and Apple has done fairly well in supporting legacy machines even past the five year end of life.
Score: 8 Votes (Like | Disagree)
laflores Avatar
161 months ago
Can any one explain to me why they are still doing this instead of putting extra work in Mavericks? Not that it bothers me, just asking

Because otherwise, people would start crying because "apple doesn't care about mountain lion any more" and some people will complain that mavericks is a piece of **** and they rather stay with snow leopard...
Score: 8 Votes (Like | Disagree)
rdlink Avatar
161 months ago
Gonna miss those cats when they're gone.
Score: 7 Votes (Like | Disagree)
iBug2 Avatar
161 months ago
(not trolling)

first time that safari has ever been snappier for me....running rMBP.....but it might also just be because safari in mavs is horrible

Are you kidding me? Safari 7.0 finally solves the memory issue which was introduced in 5.1 where when you open many tabs, web process just crashes. 7.0 does not have that, the single most annoying Safari bug in 2 years being solved finally.
Score: 5 Votes (Like | Disagree)
darkknight14 Avatar
161 months ago
Gonna miss those cats when they're gone.

Me too, every time I look at that new wave background it makes me want to go for a p***
Score: 4 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 ...
Apple Logo Spotlight

Report: Apple to Launch These New Products in 2026

Sunday November 2, 2025 5:34 am PST by
Apple is planning to launch at least 15 new products in 2026, according to Bloomberg's Mark Gurman. Gurman outlined what to expect from Apple in 2026 in the latest edition of his "Power On" newsletter. He said the company is heading "into one of its most pivotal years in recent memory," with the rollout of major new Apple Intelligence features, intense regulatory pressure on the App Store,...
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 ...
Apple Intelligence General Feature 2

New Version of Siri to 'Lean' on Google Gemini

Sunday November 2, 2025 6:06 am PST by
In his "Power On" newsletter, Bloomberg's Mark Gurman today provided an update on the status of Apple Intelligence and the plans for it in 2026. Apple is still planning to roll out its revamped version of Siri around March of next year. The release should be accompanied by the release of a new smart home display product with speaker-base and wall-mount options. A new Apple TV and HomePod...
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...
HomePod mini and Apple TV

New Apple TV and HomePod Mini Likely Launching Soon

Sunday November 2, 2025 5:49 am PST by
A new Apple TV and HomePod mini could launch as soon as this month, Bloomberg's Mark Gurman today suggested. In today's "Power On" newsletter, Gurman said that Apple retail stores are planning an overnight refresh on the evening of November 11, where changes will be made after closing, such as refreshing displays and placing new products for the following day. The timing of the overnight...
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 ...
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...