APFS
Default on every SSD, converting in place during installation. Copy-on-write, snapshots, native encryption and nanosecond timestamps, replacing a filesystem from 1998.
At launch
- Announced
- June 5, 2017
- Released
- September 25, 2017
- Follows
- Sierra (10.12)
- Followed by
- Mojave (10.14)
- Filesystem
- APFS
Overview
A new filesystem, swapped in under a running Mac.
HFS+ had been the Mac's filesystem since 1998, designed for spinning disks and showing it. APFS replaced it: built for flash, with instant copies, atomic snapshots, native encryption and crash protection — and the upgrade converted your startup disk in place, during installation, without moving your files.
Apple's own name for the release said what it was. High Sierra was Sierra's plumbing: Metal 2, HEVC video, HEIF images, external graphics support, and a Safari that began blocking cross-site trackers and auto-playing video by default.
APFS
Nineteen years of HFS+, replaced in place.
Copying a file became instant, because APFS shares the blocks until one of them changes. Snapshots are atomic. Space is shared between volumes instead of partitioned. And the conversion ran on your real disk, mid-install, without a backup restore.
The filesystem, rebuilt underneath
Features
What shipped.
Almost none of it visible, and nearly all of it still load-bearing today.
Metal 2
A substantially faster graphics stack with machine learning and VR support, and the foundation for external GPU boxes over Thunderbolt 3.
At launch
HEVC
H.265 encoding and decoding, hardware-accelerated on newer Macs — roughly the same quality as H.264 in about half the space.
At launch
HEIF
The image format iPhone had just switched to, halving photo sizes. The Mac had to understand it or nobody's library would open.
At launch
Intelligent Tracking Prevention
Safari began using on-device machine learning to cut off cross-site trackers — an industry fight that is still running.
At launch
Autoplay blocking
Video that started playing by itself was stopped by default, per site, which changed a good deal of publisher behaviour overnight.
At launch
Notes tables
Proper tables inside notes, plus pinning the notes you keep coming back to at the top of the list.
At launch
Mail split view
Composing in full screen next to the message list, with mailboxes on disk compressed to about a third of their previous size.
At launch
Photos
A rebuilt editor with curves and selective colour, persistent edits across devices, and third-party editing extensions.
At launch
The last of the 10.x
Nine more releases than anyone expected the number to take.
Mac OS X 10.0 shipped in 2001 with a version number that implied a 10.1, perhaps a 10.5. Instead the minor number kept climbing for nineteen years, through fifteen releases, three processor architectures and four names.
Big Sur finally moved it to 11 in 2020. High Sierra sits close to the end of that run — the second-to-last release of the decade and a half that the Mac spent as version ten point something.
Desktop
Autumn in the range.
The same mountains as Sierra a year later and a season on — aspens turning gold above a still lake, with fresh snow on the peaks behind.
High SierraAspens turning, above the lakeThere was only ever one. A system-wide Dark Mode did not arrive until Mojave in 2018, so this page's light and dark appearances are ours, not Apple's — the switch in the corner still works, but the desktop of the day looked like this and only this.
Lineage
Where it sits.
California landmarks from Mavericks onward — Apple's second consecutive year in the Sierra Nevada.
Compatibility
Machines that could run it.
The same machines Sierra ran on. APFS conversion was automatic on flash storage and left Fusion Drives and spinning disks on HFS+ for the time being.
- iMac
- Late 2009 and later
- MacBook
- Late 2009 and later
- MacBook Air
- Late 2010 and later
- MacBook Pro
- Mid 2010 and later
- Mac mini
- Mid 2010 and later
- Mac Pro
- Mid 2010 and later
- Memory
- 2 GB