macOS High Sierra (version 10.13) is the fourteenth major release of macOS, Apple Inc.'s desktop operating system for Macintosh computers. macOS High Sierra was announced at the WWDC 2017 on June 5, 2017 and was released on September 25, 2017. The name "High Sierra" refers to the High Sierra region in California. Its name signified its goal to be a refinement of the previous macOS version, macOS Sierra, focused on performance improvements and technical updates rather than features. This makes it similar to previous macOS releases Snow Leopard, Mountain Lion and El Capitan. Among the apps with notable changes are Photos and Safari.
macOS High Sierra is the final version of macOS to support the Unibody iMac and the Polycarbonate Unibody MacBook, as its successor, macOS Mojave, drops support for the late 2009 and final models.
System requirements
All the Macs supporting macOS Sierra support macOS High Sierra. iMac (Late 2009 or later) MacBook (Late 2009 or later) MacBook Air (Late 2010 or later) MacBook Pro (Mid 2010 or later) Mac Mini (Mid 2010 or later) iMac Pro (2017) Mac Pro (Mid 2010 or later)
macOS High Sierra requires at least 2 GB of RAM and 20.12 GB of available disk space.
It is possible to install High Sierra on many older Macintosh computers that are not officially supported by Apple. This requires using a patch to modify the install image.
Changes
Default wallpaper
The default desktop picture is an image of North Lake in the High Sierra region.
System
Apple File System
Apple File System (APFS) replaces HFS Plus as the default file system in macOS for the first time with High Sierra. It supports 64‑bit inode numbers, is designed for flash memory, and is designed to speed up common tasks like duplicating a file and finding the size of a folder's contents. It also has built‑in encryption, crash‑safe protections, and simplified data backup on the go.
Metal 2
Metal, Apple's low-level graphics API, has been updated to Metal 2. It includes virtual-reality and machine-learning features, as well as support for external GPUs. The system's windowing system, Quartz Compositor, supports Metal 2.
Media
macOS High Sierra adds support for High Efficiency Video Coding (HEVC), with hardware acceleration where available, as well as support for High Efficiency Image File Format (HEIF). Macs with the Intel Kaby Lake processor offer hardware support for Main 10 profile 10-bit hardware decoding, those with the Intel Skylake processor support Main profile 8-bit hardware decoding, and those with AMD Radeon 400 series graphics also support full HEVC decoding. However, whenever an Intel IGP is present, the frameworks will only direct requests to Intel IGP. In addition, audio codecs FLAC and Opus are also supported, but not in iTunes.
HEVC hardware acceleration requires a Mac with a sixth-generation Intel processor or newer (late 2015 27-inch iMac, mid 2017 21.5-inch iMac, early 2016 MacBook, late 2016 MacBook Pro or iMac Pro).
Other
Kernel extensions ("kexts") will require explicit approval by the user before being able to run.
The Low Battery notification and its icon were replaced by a flatter modern look.
The time service ntpd was replaced with timed for the time synchronization.
The FTP and telnet command line programs were removed.
Caching Server, File Sharing Server, and Time Machine Server, features that were previously part of macOS Server, are now provided as part of the OS.
The screen can now be locked using the shortcut Cmd+Ctrl+Q. The ability to lock screen using a menu bar shortcut activated in Keychain Access preferences has now been removed.
The 10.13.4 update added support for external graphics processors for Macs equipped with Thunderbolt 3 ports. The update discontinued support for external graphics processors in 2015 or older Macs, equipped with Thunderbolt 1 and 2 ports.
Starting with 10.13.4, when a 32-bit app is opened, users get a one-time warning about its future incompatibility with the macOS operating system.
Applications
Final Cut Pro 7
Apple announced the original Final Cut Studio suite of programs will not work on High Sierra. Media professionals that depend on any of those programs were advised to create a double boot drive to their computer.
Photos
macOS High Sierra gives Photos an updated sidebar and new editing tools. Photos synchronizes tagged People with iOS 11.
Mail has improved Spotlight search with Top Hits. Mail also uses 35% less storage space due to optimizations, and Mail's compose window can now be used in split-screen mode.