macOS 28 Update Ends Support for Encrypted Mac OS Extended Volumes

Apple is phasing out support for encrypted volumes formatted with the legacy Mac OS Extended file system in its upcoming macOS 28 operating system. Beginning next year, users with encrypted HFS+ (or HFS Plus) drives will need to take action to ensure continued access to their data.

According to a new support document released by Apple, macOS 28 will only support the Mac OS Extended file system format for volumes that are not encrypted. This change directly impacts users who rely on older external drives or other storage devices formatted with this legacy system and secured with encryption.

Users affected by this change will be faced with a choice: either decrypt their existing Mac OS Extended volumes or reformat them entirely. Apple has not publicly detailed the specific reasoning behind this deprecation, but the move is widely seen as another step in the company's ongoing transition towards its modern APFS (Apple File System). APFS, introduced as the default file system in macOS High Sierra, offers integrated encryption capabilities and is designed for contemporary storage technologies.

Starting with an earlier version, macOS 26, Apple began notifying users if they were utilizing an encrypted Mac OS Extended disk that would become incompatible with future macOS releases, including macOS 28. These notifications are intended to guide users to identify affected volumes by name. To manually check if a volume is both using the Mac OS Extended format and is encrypted, users can open Disk Utility. By selecting the volume and checking the information displayed below its name, users can see if both "Mac OS Extended" and "Encrypted" are listed. For example, a volume might be identified as "Mac OS Extended (Case-sensitive, Journaled, Encrypted)" or a CoreStorage Logical Volume with similar characteristics.

Preparing for the Transition

While unencrypted volumes using the Mac OS Extended format will continue to be supported in macOS 28 and later, the deprecation of encrypted volumes signals a clear direction for Apple's storage strategy. To prepare for the transition, Apple recommends that users back up any critical data from their affected volumes. Following the backup, users have two primary options:

The first option is to erase and reformat the volume. This process permanently deletes all existing data on the drive, but ensures full compatibility with macOS 28 and subsequent versions. Users can choose to reformat the volume using either the standard APFS format or the APFS (Encrypted) format for continued security.

The second option involves decrypting the volume. This method is not applicable to encrypted Time Machine backup disks. Users can initiate decryption by connecting the drive, entering the encryption password when prompted to unlock it, and then selecting the "Decrypt" option from the context menu. This process requires entering the encryption password again and can take a significant amount of time, especially for large volumes. The progress can be monitored via the Terminal by inputting the command "diskutil cs list".

Once a volume has been decrypted, users have the option to convert it to APFS format without erasing its contents. This is achieved through Disk Utility by selecting the volume and using the "Convert to APFS" option. For users who wish to re-encrypt their data after conversion, this can be done via the "Encrypt" option in the context menu, providing a secure APFS volume.

This change marks another milestone in Apple's efforts to modernize its operating systems and ensure optimal performance and security with its newer technologies like APFS. Users are encouraged to address any affected volumes well in advance of the macOS 28 release to avoid potential data access issues.