Information:-. Mountain Lion 2012 is the first OS X release built with iCloud??? in mind for easy setup and integration with apps. The developer preview of Mountain Lion also introduces Gatekeeper, a revolutionary security feature that helps keep you safe from malicious software by giving you complete control over what apps are installed on your Mac. The preview release of Mountain Lion is available to Mac Developer Program members starting today. Mac users will be able to upgrade to Mountain Lion from the Mac App Store??? in late summer 2012.

System Requirements
OS X Mountain Lion requires a Mac with a 64-bit kernel. Mountain Lion supports the following Mac models:
??? iMac (mid 2007 or later)
??? MacBook (13-inch Aluminum, 2008), (13-inch, Early 2009 or later)
??? MacBook Pro (13-inch, Mid-2009 or later), (15-inch, 2.4/2.2 GHz), (17-inch, Late 2007 or later)
??? MacBook Air (Late 2008 or later)
??? Mac Mini (Early 2009 or later)
??? Mac Pro (Early 2008 or later)
??? Xserve (Early 2009)

Known issues
- Installing OS X 10.8 over 10.7.2 or earlier with FileVault turned on may fail
- Upgrades over Lion Server will offer to migrate data again in Setup Assistant even though an in place migration has already succeeded.
- Entering your Apple ID in the Setup Assistant does not sign into iCloud
- Migration does not migrate RADIUS configurations
- Creating an iCloud account using a non-me.com address in the Setup Assistant requires verification before it can be used in Mail, Contacts, and Calendars.
- Some Apple menu items such as Restart may not work when a sandboxed app is in the foreground
- Twitter accounts added in Developer Preview 1 will need to be re-added after installing Developer Preview 2
- The first time an unsigned or unidentified app is launched when "Mac App Store" or "Mac App Store and identified developers" is selected in the Security & Privacy pref pane, the exception mechanism may fail. Subsequent attempts to run the application with an exception will work as expected.
- iTunes no longer syncs Notes
- Notes shared via Messages may not include note content
- After quitting and reopening Messages, the message window is blank. Continuing a conversation will bring the data back.