Apple just saved macOS 28 early adopters from a massive, tedious headache. The company quietly updated its migration guidance regarding legacy storage formats, finally allowing users to convert encrypted HFS+ drives directly to APFS.
Previously, users were facing the prospect of waiting hours—or even days—for a preliminary decryption process to finish. This silent update to Apple's support documentation removes a significant roadblock for veteran Mac users with vast archives of external storage.
Streamlining the macOS 28 Transition
In early July, Apple dropped a bombshell support document detailing a strict new file system rule. The company stated that starting with macOS 28, "the Mac OS Extended file system format will be supported only for volumes (disks and other storage devices) that aren’t encrypted."
Mac OS Extended, also known as HFS+, was the default Apple file system for nearly two decades before APFS replaced it. That initial mandate meant anyone clinging to encrypted HFS+ external drives faced an agonizing set of chores to maintain access to their files.
Alternatively, erasing the drive meant users had to secure a secondary drive just to temporarily offload their data during the reformat. Fortunately, Cupertino realized how miserable that workflow actually is. Apple has completely revised the page, ditching the multi-step decryption mandate and introducing a highly requested direct-conversion option.
Executing the Direct APFS Conversion
You can now bypass the decryption phase entirely, jumping straight from an encrypted HFS+ volume to an encrypted APFS volume. The newly outlined steps in Disk Utility are straightforward and save massive amounts of time by converting the file system architecture in place.
According to the updated support page, users can achieve the direct conversion by following these specific steps:
- Open Disk Utility, located in the Utilities folder of the Applications folder (or use Spotlight to find and open it).
- From the View menu in the menu bar, choose Show Only Volumes. This step ensures you are targeting the specific partition rather than the entire physical disk.
- In the sidebar of Disk Utility, select the name of the specific volume you wish to upgrade.
- From the Edit menu in the menu bar, choose Convert to APFS, then click Convert to confirm the action.
- Quit Disk Utility when the conversion is done.
By handling the conversion and encryption translation simultaneously, the system minimizes intense read/write wear on older mechanical drives. Users retain their original passwords and immediately benefit from APFS features like faster directory sizing and improved crash protection.
The Time Machine Exception
While this updated workflow eliminates a massive friction point for standard external drives, it isn't a universal magic wand. Apple explicitly warns that "this solution doesn’t apply to encrypted Time Machine backup disks."
Legacy Time Machine backups relied heavily on a complex web of directory hard links to function on the older HFS+ architecture. Because APFS handles backups entirely differently—utilizing modern file system snapshots instead of hard links—an in-place conversion of these older backup drives is technically unfeasible.
If you are managing older, encrypted Time Machine backups on legacy HFS+ drives, this shortcut will fail. You cannot cut corners here, and relying on obsolete backup formats is a recipe for disaster.
Instead, you need to bite the bullet and manually migrate your archived backups to a freshly formatted APFS drive ahead of the macOS 28 rollout later this year. Delaying this chore simply puts your historical data at risk of being locked out entirely when you finally update your operating system.