MacOS 28 Will Drop Support for Encrypted HFS+ Drives

Apple’s next major macOS release will cut off a specific category of older storage: encrypted drives formatted as Mac OS Extended, the file system that predated APFS by decades. The company published a support document outlining the change and, more usefully, explaining exactly what users need to do before upgrading.

The practical stakes are narrow but real. Unencrypted Mac OS Extended volumes will continue to work in macOS 28 and later. The break applies only to encrypted HFS+ volumes, the kind that older encrypted external hard drives typically use.

A File System Apple Has Been Phasing Out Since 2017

Apple introduced APFS (Apple File System) as the default for Macs with macOS High Sierra, replacing Mac OS Extended (also called HFS+, or HFS Plus) after the older format had served as the Mac’s primary file system for roughly two decades. APFS was designed from the start with solid-state storage and encryption in mind, offering native encryption as a built-in feature rather than a layer bolted on top. The transition was gradual: Apple kept reading and writing Mac OS Extended volumes, just stopped creating them by default.

Dropping encrypted HFS+ support is a logical next step in that retirement, even if Apple has not stated that explicitly. The company has offered no public reason for the change. The most plausible read is that maintaining encrypted HFS+ support requires keeping legacy CoreStorage infrastructure alive, and at some point the engineering cost stops being worth it.

What macOS 26 Will Tell You Before macOS 28 Arrives

Apple is building in an early-warning system. Starting with macOS 26, a Mac may notify users when it detects an encrypted Mac OS Extended disk that will stop working in macOS 28. The alert identifies the affected volume by name, so users know exactly which drive requires attention.

Anyone who wants to check manually can open Disk Utility, select a volume, and read the format details listed beneath its name. A volume showing something like “CoreStorage Logical Volume • Mac OS Extended (Case-sensitive, Journaled, Encrypted)” is affected. A volume that shows Mac OS Extended without the Encrypted label is not.

Two Paths Forward, One of Which Deletes Your Data

Apple outlines two options for affected drives. Reformatting erases the volume entirely and sets it up fresh in APFS or APFS (Encrypted) format through Disk Utility. Decrypting preserves existing data: connect the drive, unlock it with its password, then Control-click its icon in the Finder and choose Decrypt, entering the password a second time to start the process.

Apple flags that decryption “takes time, especially for large volumes,” and that progress can be checked in Terminal. Once decrypted, the volume can optionally be converted to APFS without erasing via Disk Utility’s Convert to APFS option, and re-encrypted afterward if desired. One important carve-out: this decryption path does not apply to encrypted Time Machine backup disks, which sit in a different category entirely.

The gap between macOS 26 and macOS 28 is the window Apple is giving users to sort this out. That is a reasonable runway, assuming users pay attention to the notification when it appears. The risk is that many people store encrypted external drives in drawers and only plug them in occasionally, which means the warning could appear once and then be forgotten before the incompatibility actually bites.

For most Mac users, this will require no action at all. If your external drives are already formatted as APFS, or if they are unencrypted Mac OS Extended volumes, nothing changes. The group that needs to act is specifically those running older encrypted external hard drives that were set up before APFS became standard, which points largely at drives formatted years ago on older Macs. If you are unsure, a quick check in Disk Utility now takes about thirty seconds and answers the question definitively. Back up any affected drive before touching its format settings, regardless of which path you choose.