New Apple File System Coming in macOS High Sierra Won't Work With Fusion Drives
Sep 18, 2017 10:28 am PDT by Juli Clover
When macOS High Sierra is released to the public next week, the new Apple File System (APFS) feature will be limited to Macs with all-flash built-in storage, which means it won't work with iMacs and Mac minis that include Fusion Drives.

Macs with Fusion Drives were converted to APFS during the beta testing process in the first macOS High Sierra beta, but support was removed in subsequent betas and not reimplemented.

With the release of the Golden Master version of the software, Apple has confirmed APFS will not be available for Fusion Drives and has provided instructions for converting from APFS back to the standard HFS+ format.


Public Beta testers who had a Mac with a Fusion Drive converted to APFS will need to follow a long list of instructions to convert back to HFS+, including making a Time Machine Backup, creating a bootable installer, and using Disk Utility to reformat their Macs and reinstall macOS High Sierra.

Apple on September 5 published a support document confirming compatibility. When customers with an all-flash machine upgrade to macOS High Sierra install the update next week, their drives will be converted to AFPS. Apple explicitly says "Fusion Drives and hard disk drives aren't converted."

Apple says APFS will not be supported on Fusion Drives "in the initial release of macOS High Sierra," which suggests support could be added for Fusion Drives at a later date after lingering bugs are worked out.

Apple File System is a more modern file system than HFS+ and is optimized for solid state drives. It is safe and secure, offering crash protection, safe document saves, stable snapshots, simplified backups, and strong native encryption.


It's also more responsive than HFS+ with features like instant file and directory cloning, fast directory sizing, high performance parallelized metadata operations, and sparse file writes.

Apple plans to release macOS High Sierra on Monday, September 25.

Related Roundup: macOS High Sierra

Top Rated Comments

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10 months ago
Classic Tim Cook Apple...
Rating: 58 Votes
10 months ago
That's going to cause some serious Fusion Confusion™.
Rating: 53 Votes
10 months ago

Shame I thought they'd ironed these kinks out during the beta phase - they've had over a year now to get it work with Fusion Drives and hard drives.

Filesystems are one part of an OS where I really don't want the developers to rush, I want all the bugs thoroughly ironed out. Because that's where I keep all my stuff.
Rating: 42 Votes
10 months ago
Apple have so lost the plot it's scary!
Rating: 33 Votes
10 months ago
Yikes. Probably should have made that call before beta 1...
Rating: 32 Votes
10 months ago
With every move Apple makes in the past couple of years, they are bringing me closer and closer to the day when I completely leave the ecosystem, both for computers and smartphones.
Rating: 29 Votes
10 months ago
Gonna be a bunch of people upset for no reason other than they don't get something others got. They have no idea the benefits this change brings but damned if they'll let that lack of knowledge stop them from complaining!
Rating: 24 Votes
10 months ago

With every move Apple makes in the past couple of years, they are bringing me closer and closer to the day when I completely leave the ecosystem, both for computers and smartphones.


If you think your Windows or Linux experience is going to have fewer kinks then I have some bad news for you...
Rating: 23 Votes
10 months ago

Yikes. Probably should have made that call before beta 1...

People running betas should expect to wipe their device at some point. Sometimes you get lucky and may not need to. That does not change what your expectations should be.
Rating: 21 Votes
10 months ago
Wow...just wow.
Rating: 21 Votes

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