Those Macs that use Fusion Drives (like the iMac, for example) or good old hard disk drives will not be converted, period.
So basically, if you install APFS on any Mac that uses a solid-state drive as a built-in boot drive, it will automatically convert to APFS and you will not have a choice. You can’t opt out of the transition to APFS. (Rocket Yard emphasis)
Fusion Drives and hard disk drives (HDDs) aren’t converted. When you install macOS High Sierra on the built-in solid-state drive (SSD) of a Mac, that drive is automatically converted to APFS. APFS features strong encryption, space sharing, snapshots, fast directory sizing, and improved file system fundamentals. Probably the most important information from Apple is this quote:Īpple File System (APFS) is the default file system in macOS High Sierra for Mac computers with all-flash storage. Thanks to sharp-eyed Rocket Yard commenter Chris pointing us to an Apple support document, we now have a bit more information on macOS High Sierra, Apple File System, and how it all works on Macs and on volumes that are formatted with the legacy HFS+ file system.Ĭhris pointed us to this Apple tech document, titled Prepare for APFS in macOS High Sierra.
