Mac OS X 10.8

OS X 10.8, marketed as "Mountain Lion", is a major release of the Mac OS X operating system that was developed by Apple Inc. It was announced on February 16, 2012 and the first developer beta was released on the same day. Its goal was to incorporate tighter integration between the Mac and Apple's iOS mobile operating system through iCloud online services. Mountain Lion was released on July 25, 2012 through the Mac App Store for 19.99. It was the last major release to be sold as future versions were made available as free downloads. On June 23, 2021, Apple made Mountain Lion freely available for all users of older Mac hardware.

Appearance
The appearance of Mountain Lion is mostly unchanged from Lion (10.7) and Snow Leopard (10.6). It still uses the Aqua user interface, as well as the steel window color.

New features and updates

 * iCloud -- Mountain Lion plans to fully embrace the abilities of iCloud. It will be using it for iMessages, Reminders, Game Center, Mail, Notes, and many other features.
 * Messages -- Mountain Lion will bring the popular iMessage feature from the iPhone, iPad, and iPod Touch to Mac. You will be able to send and receive messages for free from your Mac. It can be used exactly like iOS.
 * Reminders -- Mountain Lion will feature Reminders. It will pop up reminders at you from both your Mac and other iDevices. It will use iCloud to sync reminders to all your devices.
 * Notes -- This one is pretty clear. Notes for Mac. It will use iCloud to sync your notes to all your devices. You can also create a note and cut it out and place it on your desktop just like Sticky Notes from Windows 7.
 * Notification Center -- OS X Mountain Lion will also have the Notification Center. It will have notifications about your Mac and Mac Apps, along with your other iDevices that have iCloud set up. It will even have a Gesture that will pull up the Notification Center just like on iOS 5, which is done by swiping two fingers to the left.
 * Share Sheets -- Now OS X will have the useful share Sheets. Just look for the sharing icon on some apps to show a send to... just like on iOS.
 * Twitter -- OS X 10.8 will also have enhanced Twitter capability. You will be able to tweet right from your apps. Also when you get a mention or a direct message, a Twitter notification appears on your desktop.
 * Game Center -- One of the most important add-ons is Game Center. With Game Center you will be able to see what your friends are doing, check your stats, and more just like you have iOS.
 * AirPlay Mirroring -- Now, just like on iOS you will be able to wirelessly mirror your Mac to your Apple TV.
 * Gatekeeper-- Makes the Mac safer than ever by helping to prevent users from unknowingly downloading and installing malicious software. And it gives you control over which applications to download and run on your Mac. Now you can choose from three security options. You can download and run applications from anywhere, just as in OS X Lion. To be even safer, download and run apps from the Mac App Store and apps with a Developer ID; or download and run only apps from the Mac App Store — the safest setting of all. Gatekeeper lets you decide which setting is best for you.
 * More Chinese features – has additional features for users in China, including support for Baidu as an option for Safari's search engine, QQ, 163.com and 126.com services for Mail, Contacts and Calendar, Youku, Tudou and Sina Weibo are integrated into share sheets.
 * Time Machine is able to do rotating backups on more than one storage medium.

Renamed applications

 * Address Book is renamed "Contacts"
 * iCal is renamed "Calendar"
 * iChat has been enhanced and renamed "Messages" (see above)

Dropped features

 * RSS support in Mail and Safari has been removed.
 * Software Update – has been unified into the Mac App Store.
 * X11.app – users are directed to the open source XQuartz project instead.