If you're using an older encrypted external drive with your Mac, Apple has a critical update for you. The company is ending support for encrypted Mac OS Extended (HFS+) volumes, a change that will arrive with next year's major macOS update.
This move will force users with these legacy drives to take action or risk losing access to their data. Apple announced the details in a new support document, confirming that macOS 28 will be the final cutoff.
The End of an Era for Encrypted HFS+
Once you upgrade to macOS 28, any drive using the encrypted HFS+ format will become inaccessible. While unencrypted HFS+ drives will still work for now, this signals a definitive push toward the modern Apple File System (APFS).
This change primarily affects users with older encrypted external hard drives, some of which may be used for Time Machine backups. To help users prepare, Apple says it will begin showing warning notifications in macOS 26 if an affected drive is detected.
What You Need to Do
Here’s what you need to do before upgrading to macOS 28 to keep your data safe. You have two main options: reformatting the drive or decrypting it first.
- Reformat the drive: Back up all your data, erase the drive using Disk Utility, and reformat it as APFS (Encrypted).
Be warned: this process permanently deletes all content on the drive, so a complete backup is essential.
- Decrypt the drive: Unlock the drive with its password, then use the Finder to begin the decryption process.
Apple notes that this can be a very slow process, especially for large hard drives with terabytes of data.
After decryption, an HFS+ drive can be converted to APFS without erasing its contents. You can then re-apply encryption in the new format.
A Critical Warning for Time Machine Users
If your Time Machine backup drive is an encrypted HFS+ volume, your only option is to back up the data elsewhere, reformat the drive as APFS, and start a new backup from scratch.
Part of a Broader Mac Modernization
This file system update is part of Apple's larger strategy of phasing out legacy technologies and modernizing the Mac platform.