GoKawiilmacOS 27 drops all support for CoreStorage and encrypted HFS+ volumes
A developer reports that macOS 27 can no longer mount, convert, or erase CoreStorage and encrypted HFS+ volumes, even manually through Disk Utility or the command line. Attempts to mount these volumes return errors such as a DiskManagement disenter failure, and diskutil's unlock command falsely claims the volume is locked when it is already unlocked. The system also shows a boot-time dialog warning that macOS 28, not macOS 27, will drop support—contradicting the behavior users are experiencing now.