{"id":52602,"date":"2026-07-14T14:26:51","date_gmt":"2026-07-14T18:26:51","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=52602"},"modified":"2026-07-14T14:26:51","modified_gmt":"2026-07-14T18:26:51","slug":"sunsetting-corestorage","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2026\/07\/14\/sunsetting-corestorage\/","title":{"rendered":"Sunsetting CoreStorage"},"content":{"rendered":"

Apple<\/a>:<\/p>\n

In macOS 28 and later, the Mac OS Extended file system format will be supported only for volumes (disks and other storage devices) that aren’t encrypted. For future macOS compatibility, either decrypt or reformat any encrypted Mac OS Extended volumes.<\/p><\/blockquote>\n\n

I think Apple removed the user interface for creating such volumes way back in Big Sur. It’s not really surprising that they’re going away, although only offering a year of warnings seems rather aggressive. Many people delay updating to major OS versions or wait until they get a new Mac. There will be users that switch to a Mac that can only run macOS 28 and get rid of their old one before realizing that some drive they haven’t connected in a while won’t mount.<\/p>\n\n

The other surprising part is that Apple’s options—reformat or decrypt—are not great. During the initial transition to APFS<\/a>, macOS would transparently convert an encrypted HFS+ boot volume to encrypted APFS without rewriting any data. This functionality is nominally still available via the diskutil apfs convert<\/code> command, but Apple hasn’t mentioned this or built an automatic upgrader GUI.<\/p>\n\n

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[Decrypting] doesn’t apply to encrypted Time Machine backup disks.<\/p>\n<\/blockquote>\n\n

It’s obvious why. The old Time Machine format with hard links is totally different from the new one based on APFS snapshots. But this means that you’ll either need to buy a new Time Machine drive for use with macOS 28 or delete your backup history. Even if you keep the old drive, you’ll need an older boot drive or an old Mac in order to be able to access it.<\/p>\n\n

Previously:<\/p>\n