Fusion Drives not supported in macOS High Sierra

The good news, which you probably already know about, is that macOS High Sierra will be released six days from now. The bad news is that the new Apple File System will only work on Macs which have built-in all-flash storage.

To put it differently, it will not work with Mac minis and iMacs that boast Fusion Drives.

During the beta testing phase in the initial macOS High Sierra beta, Macs using Fusion Drives were switched over to APFS, but in later betas support was stopped and never re-implemented.

When it released the software’s Gold Master version, Apple officially announced that APFS will not be released for Fusion Drives. The company offered instructions on how to convert to the conventional HFS+ format.

If you are a Public Beta Tester and your Mac uses a Fusion Drive that was converted to Apple File System, there’s a long list of things you will have to do to make the transition back to HFS+. This includes setting up a bootable installer, creating a Time Machine Backup, reformatting your Mac using Disk Utility, and finally re-installing macOS High Sierra.

Earlier this month Apple released a support document explaining compatibility. It clearly stated: “Fusion Drives and hard disk drives aren’t converted.” 

Apple added that there will not be support for APFS on Fusions Drives in the first release of macOS High Sierra. This hints at possible support for Fusions Drives in later releases, after all the bugs have been ironed out.

APFS offers optimised performance on solid state drives and is more modern than HFS+. It is also secure, safe and offers stable snapshots, secure document saves, crash protection, strong native encryption and simpler backups.

With features such as instant directory and file cloning, sparse file writes, fast parallelised metadata operations, and fast directory sizing it is also bound to offer better responsiveness that HFS+.

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About the author


I've been a passionate evangelist for Apple and the Macintosh throughout my working life, my first love was a Quadra 605 working with a small creative agency in the south of Norfolk UK in the mid 1990's, I later progressed to other roles in other Macintosh dominated industries, first as a Senior graphic designer at a small printing company and then a production manager at Guardian Media Group. As the publishing and printing sector wained I moved into Internet Marketing and in 2006 co-founded which grew to become one the top 200 visited sites in the US (according to Quantcast), at its peak receiving over 15 million visits per month. For the last ten years I have worked as an Affiliate and Consultant to many different business and start ups, my key skill set being online marketing, on page monetisation, landing page optimisation and traffic generation, if you would like to hire me or discuss your current project please reach out to me here.

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