macOS 27 drops CoreStorage support
The gist
Blogger Wade Tregaskis reports macOS 27 Golden Gate cannot mount, convert or erase CoreStorage encrypted HFS+ volumes.
Users of older encrypted drives may lose normal access to that storage.
How it unfolded
- Jul 8, 2026Apple announces that starting with macOS 28, Mac OS Extended (HFS+) will be supported only for unencrypted volumes; users with encrypted volumes will need to decrypt or reformat them.
- Jul 14, 2026Michael Tsai publishes a blog post titled "Sunsetting CoreStorage".
- Nov 1, 2026Wade Tregaskis reports macOS 27 Golden Gate does not support CoreStorage / encrypted HFS+ volumes: they can't be mounted, converted to APFS or erased through normal means, with Disk Utility and diskutil mount failing.