macOS Sierra (version 10.12) is the thirteenth major release of macOS (previously OS X), Apple Inc.'s desktop and server operating system for Macintosh computers. It is the successor to OS X El Capitan and will focus on Continuity, iCloud and windowing enhancements, and support for Apple Pay and Siri. Apple rebranded OS X into macOS, reminiscing the old naming scheme used since Mac OS 7.6.
The first beta of macOS Sierra was released to developers shortly following the 2016 WWDC keynote on June 13, 2016. macOS Sierra will be available to end users in the fall of 2016 as a free upgrade through the Mac App Store.
Features:
Continuity, iCloud and Apple Pay
The computer can be unlocked automatically when the user wears a paired Apple Watch. The clipboard can be shared across nearby macOS Sierra and iOS 10 devices for cut, copy and paste. iCloud Drive will be able to sync files that are located in the Documents directory and on the desktop, in addition to the iCloud Drive directory. Old files across the system can also be uploaded automatically and be deleted locally as the computer runs out of space. Apple Pay will be made available to online shops and users can authenticate purchases through a connected iPhone or Apple Watch.
Windowing enhancements
Applications that support multiple windows will support multiple tabs within a single window. Picture in Picture, a miniature video player that floats on top and follows the user across spaces, will be supported.
Siri
The Siri intelligent assistant will be integrated into the system. Users can access it via the Dock, the menu bar or a keyboard shortcut and results are shown with an interface in the upper-right corner. Results are interactive and be dropped into other applications, for instance, pictures from a web search can be dragged into a document.
Photos
Using deep learning, Apple added facial recognition to Photos. It groups similar pictures together using faces, locations and object recognition to create 'memories'. Memories contain picture slideshows with transitions and music selected by the algorithm, which can be modified to the user's liking.
Apple File System
Apple announced a preview of a new file system, called Apple File System (APFS). It is intended for SSDs and will adopt several features introduced by ZFS, such as snapshots and cloning, as well as native support for features that Apple already provides through HFS Plus and supplementary software, such as encryption and TRIM. Usage is currently experimental and a release is planned for 2017. Apple plans to make it open source.
macOS Sierra supported devices:
- iMac (late 2009 or newer)
- MacBook Air (2010 or newer)
- MacBook Pro (2010 or newer
- Mac mini (2010 or newer)
- MacBook (2009 or newer)
- Mac Pro (2010 or newer)
To install:
1) Mount .dmg.
2) Move the file 'Install 10.12 Developer Preview' to application folder.
3) Install it..!!
4) Sorry my bad English. I'm from Brazil..!!
5) Enjoy it..!!

Install macOS 10.12 Sierra - Developer Preview Beta 1 - Original AppStore