The first developer preview of OS X 10.8.0 was seeded as a download on February 16, 2012 for members of the Apple Developer program. The second and third developer previews were released on March 16 and April 18, respectively. The fourth developer preview was released on June 11 during the 2012 Worldwide Developers Conference.
- Mac OS X 10.8 Mountain Lion Developer Preview Released as Dev Download by Paul Horowitz, OS X Daily. 2012-02-16.
- OS X 10.8 Mountain Lion Developer Preview 2 Seeded to Developers by Eric Slivka, MacRumors. 2012-03-16.
- Apple releases OS X Mountain Lion Developer Preview 3, AppleInsider. 2012-04-18.
- Apple seeds OS X Mountain Lion Developer Preview 4 (Release note) by Jake Smith, 9to5Mac. 2012-06-11.