During the last evening the company Apple launched OS X Mountain Lion Developer Preview 3 build 12A206j for Mac OS X application developers, this is probably the last version available before the official release. In the documentation available with the update, Apple says that MacBooks released in mid/late 2007 are incompatible with this build, but until the final release, Apple will resolve the incompatibility issues.
The new build of OS X Mountain Lion can be downloaded by application developers for Mac OS X from their dedicated portal on the Apple website.
A pre-release version of the OS X Mountain Lion software is now available. If you have build 12A178q or higher installed, the new build of OS X Mountain Lion is available through Software Update. A new Server build will be available later. Detailed instructions for installing this build can be found in the OS X Mountain Lion discussions. Please review these instructions completely before attempting to install the software.
Important: MacBook Pro 3,1 is not supported in this build of Mountain Lion. Future developer previews will restore support for this configuration.
InstallationA pre-release version of the OS X Mountain Lion software is now available via Software Update in the Mac App Store. You will need to have build 12A178q or higher installed in order to see the update. Once the update is complete, your system will be at build 12A206j.
1) Click on the Apple menu, then click on Software Update. The Mac App Store will launch and display your available updates. Note: You can still access the Software Update in all of the same ways, only now the Mac App Store will launch and open the Updates tab.
2) In the section with the Mountain Lion icon, titled "Software Update," click on the "...More" link.
3) Find the update called "Mountain Lion Developer Preview Update 10.8", and click the corresponding Update button for this update to install. The update will begin downloading, and when prompted, click "Restart" to install the update.
