OS X Mountain Lion 10.8.1 (Build 12B13) Released To Developers


Just over two weeks after its initial public release, OS X Mountain Lion has released the first developer’s beta update which can now be downloaded through the Mac Developer Center web portal. The update is labelled as OS X Mountain Lion 10.8.1 build 12b13 and is downloadable as 38.54MB DMG file. While some might have hoped this update will fix the extensive battery drain issues experienced by MacBooks, unfortunately it does not address that problem. Apple has however asked developers to focus on testing Active Directory, Microsoft Exchange in Mail, PAC Proxies in Safari, SMB, USB, and WiFi and Audio when connected to the Apple Thunderbolt Display, according to 9to5Mac.

Below are the official release notes:

OS X Mountain Lion 10.8.1 build 12B13 Seed Note

OS X Mountain Lion Update 10.8.1 is an update to OS X Mountain Lion 10.8.

Installation Instructions

The OS X Mountain Lion 10.8.1 Update (Delta) updates OS X Mountain Lion 10.8 GM.

Please be aware that you will not be able to revert back to your previous system after updating. Please install this update on a system you are prepared to erase if necessary.

Known Issues

– None

Focus Areas

– Active Directory

– Microsoft Exchange in Mail

– PAC proxies in Safari



– Wi-Fi and audio when connected to Thunderbolt display

Apple has neither introduced Facebook integration nor the iMessage phone number merging feature in this update.


  • i feel like Mountain lion was not ready for public, but they released it anyway; the same thing that happened to iPhone 4. I am not sure why apple is falling behind every year. Samsung has released quad core smartphone long time ago. Also, i have a feeling that iPhone 5 will have the same processor as iPad 3. Apple needs more employees! 🙂

  • MountainJew

    It doesn’t matter if Samsung releases a quad core phone or not. Specs do not matter on a device; Optimization is what matters as opposed to raw specs.

  • Yep. The hardware race is over. It’s all about software now and user experience now.

  • I see your point,but I expect from Apple to make high end products using latest tech available. hardware and user exp are tied together. Crapy hardware = crapy user exp. Let me clarify, by having a high end hardware, devs can make better games, OS can be enriched, so all that leads to better user exp. I hope you guy get my point. Also, the price; Apple is pricy, and they HAVE to justify that price.

  • maybe silicon race is over, but there are a lot of other things that can be upgraded. New batteries are about to come, nano tech baby. I cannot wait for that moment, I am tired of recharging my phone every day. Also wireless charging. There are still lots of thing going one when it comes to hardware race.

  • I totally agree. New tech is always around the corner but I think it should come down to how it is implemented for the best user experience, instead of just saying “we’re first!” and putting it into a phone. Look at NFC for example…it’s been around in BlackBerrys for a while, but it’s not a popular standard yet.

  • excaliburca

    Kinda glad I’ve held off on upgrading the Macs here at work. Will wait till they address the battery issues before committing to it.

  • xxJDxx

    Absolutely. Unless Apple starts releasing multiple devices a year they wont be able to keep up with samsung’s nearly ‘new phone every two months’ pace. Remember the tegra 2? that was plagued with problems because it was rushed to market to compete. I finally unloaded my galaxy tab a few weeks ago for less than half what I paid for it, wont make that mistake again. Like the OP said, people expect quality from apple, rushing to market just to be ‘first’ wont get you quality.