The "Mac OS X 10.8 Mountain Lion" was released a day after Apple reported disappointing results that hammered its shares.
Mountain Lion, first unveiled in June during Apple's annual Worldwide Developers Conference, is available as an upgrade from the previous two operating systems Lion and Snow Leopard for $19.99. Macs purchased on or after June 11 will receive a free upgrade, the company said.
The update includes more than 200 new features, including integration with iCloud, desktop versions of Messages and Game Center, a new Notification Center, according to a press release.
A future update for the new operating system will bring Facebook directly onto the Mac, Apple said.
