OS X Mountain Lion

OS X Mountain Lion, or OS X 10.8, is a version of OS X released in 2012. It introduced various revamps to the Lion user interface and fixed many of the paradigms that were found to be controversial in Lion. A new feature to OS X, Gatekeeper, prevents unsigned code from running on a Mac by default (in an attempt to prevent malware), although it can be disabled. A system-wide notification system has also been ported from iOS, known as Notification Center.

Like in iOS 11, this version of OS X is the first to drop support for 32-bit kernels and corresponding 32-bit EFI BootROM Macs. The decision to drop 32-bit architectures was made relatively late in the development process, as Beta 1 (12A128p) shipped with a 32-bit kernel. This version drops support for NVIDIA GeForce 6000/7000 Series, ATi Radeon X800/X1000 Series and Intel GMA 900/950/3150/X3100 (Mobile 965 Express Chipset Family) graphics cards.

Software Update is also now part of the App Store in this version of OS X.