Apple today seeded build 12F20 of OS X 10.8.5 to developers, offering a fourth 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 12F17.

Mountainlion12f20
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.

Update: One tipster says the update fixed the Adobe Photoshop flickering issue that was reported last last month.

Top Rated Comments

gnurf Avatar
140 months ago
A pretty irrelevant post considering this a about Mavericks, not iOS.

Except it isn't about Mavericks :)
Score: 7 Votes (Like | Disagree)
HolgerR Avatar
140 months ago
A pretty irrelevant post considering this a about Mavericks, not iOS.

No. It's not.
Score: 3 Votes (Like | Disagree)
ValSalva Avatar
140 months ago
Will there be a 10.8.6?

Yays? Nays?

I think yes. 10.8.5 will be out well before Mavericks. Then work on 10.8.6 will begin. I highly doubt there will be any 10.8.7 though.
Score: 2 Votes (Like | Disagree)
cbs20 Avatar
140 months ago
Have any of you guys any experience in how things are running with the latest 10.8.5 vs the 10.9 dev ?

I had the first 10.9 dev build installed and it runs like a dream, but things like some adobe apps breaks, but I would hate going back to 10.8 (standard) because that was dreadful too... so currently i am running windows8.1 but would prefer to get back on a speedy osx :)

So if any of you for some reason have had too much time and have a feeling of both, let me know! thanks :P

First thing you have to consider is 10.8 is a much more established OS and 10.9 is only in beta. When DP1 for 10.9 was released that was the first time anybody at Adobe could get their hands on the OS and start optimizing applications to run in 10.9. On top of that the OS is constantly changing until its final release and applications may need to be tweaked with these changes to make sure they work with the OS. You can't make a good comparison of a beta OS to an established OS. Wait until 10.9 is released and app developers release their updates and then you can judge what OS to use.
Score: 1 Votes (Like | Disagree)
Mr. Wonderful Avatar
140 months ago
^As much as I hate waiting longer for new releases, I think year and a half OS X development cycles might be a good thing for everyone. It's more time to add more significant features, and it allows more time for the current OS to become rock solid, which is great for casual users and enterprise. I know I felt like Lion never got truly stable.
Score: 1 Votes (Like | Disagree)
Garrod Avatar
140 months ago
They should do weekly iOS 7 beta seeds too.

A pretty irrelevant post considering this a about Mavericks, not iOS.
Score: 1 Votes (Like | Disagree)

Popular Stories

reset password request iphone

Warning: Apple Users Targeted in Phishing Attack Involving Rapid Password Reset Requests

Tuesday March 26, 2024 4:34 pm PDT by
Phishing attacks taking advantage of Apple's password reset feature have become increasingly common, according to a report from KrebsOnSecurity. Multiple Apple users have been targeted in an attack that bombards them with an endless stream of notifications or multi-factor authentication (MFA) messages in an attempt to cause panic so they'll respond favorably to social engineering. An...
Generic iOS 18 Feature Purple

iOS 18: What to Expect From 'Biggest' Update in iPhone's History

Wednesday March 27, 2024 11:10 am PDT by
At least some Apple software engineers continue to believe that iOS 18 will be the "biggest" update in the iPhone's history, according to Bloomberg's Mark Gurman. Below, we recap rumored features and changes for the iPhone. "The iOS 18 update is expected to be the most ambitious overhaul of the iPhone's software in its history, according to people working on the upgrade," wrote Gurman, in a r...
maxresdefault

Apple to Launch New iPad Pro and iPad Air Models in May

Thursday March 28, 2024 11:07 am PDT by
Apple will introduce new iPad Pro and iPad Air models in early May, according to Bloomberg's Mark Gurman. Gurman previously suggested the new iPads would come out in March, and then April, but the timeline has been pushed back once again. Subscribe to the MacRumors YouTube channel for more videos. Apple is working on updates to both the iPad Pro and iPad Air models. The iPad Pro models will...
maxresdefault

Apple Announces WWDC 2024 Event for June 10 to 14

Tuesday March 26, 2024 10:02 am PDT by
Apple today announced that its 35th annual Worldwide Developers Conference is set to take place from Monday, June 10 to Friday, June 14. As with WWDC events since 2020, WWDC 2024 will be an online event that is open to all developers at no cost. Subscribe to the MacRumors YouTube channel for more videos. WWDC 2024 will include online sessions and labs so that developers can learn about new...
apple maps 3d feature

Apple Maps May Gain Custom Routes With iOS 18

Tuesday March 26, 2024 3:10 pm PDT by
Apple may be planning to add support for "custom routes" in Apple Maps in iOS 18, according to code reviewed by MacRumors. Apple Maps does not currently offer a way to input self-selected routes, with Maps users limited to Apple's pre-selected options, but that may change in iOS 18. Apple has pushed an iOS 18 file to its maps backend labeled "CustomRouteCreation." While not much is revealed...
General iOS 17 Feature Orange Purple

Apple Releases Revised Versions of iOS 17.4.1 and iPadOS 17.4.1 With Updated Build Number

Wednesday March 27, 2024 5:59 am PDT by
Apple on late Tuesday released revised versions of iOS 17.4.1 and iPadOS 17.4.1 with an updated build number of 21E237, according to MacRumors contributor Aaron Perris. The updates previously had a build number of 21E236. The revised updates are available for all iPhone and iPad models that are compatible with iOS 17 and iPadOS 17, but they can only be installed via the Finder app on macOS...
applephilschiller

Apple's Phil Schiller Works 80 Hours a Week Overseeing App Store

Wednesday March 27, 2024 2:03 pm PDT by
With the App Store and app ecosystem undergoing major changes in the European Union, The Wall Street Journal today shared a profile on App Store chief Phil Schiller, who is responsible for the App Store. Though Schiller transitioned from marketing chief to "Apple Fellow" in 2020 to take a step back from Apple and spend more time on personal projects and friends, he is reportedly working...