With the release of macOS 27 (Golden Gate), Apple appears to have moved beyond the deprecation of CoreStorage and encrypted HFS+ volumes into a state of functional incompatibility. While macOS 15 Sequoia had already begun to cripple tools for these older technologies, it still allowed for some level of manual unlocking and data access. In macOS 27, however, these volumes have become effectively inaccessible through standard interfaces. Users report that Disk Utility and the `diskutil` command-line tool fail to mount these volumes, often returning cryptic errors or misleading messages suggesting the volumes are locked even when they are already unlocked.
This image represents the macOS 27 (Golden Gate) operating system discussed in the opening paragraph.
The failure extends to management and migration tasks. Users attempting to convert these volumes to the modern APFS file system find that the conversion process fails with generic exit codes, and attempts to erase the volumes are blocked by a persistent "Resource busy" (EBUSY) error. Interestingly, the source indicates that the system can still mount these volumes via low-level commands like `mount_hfs`, but only in a read-only capacity. Any attempt to perform read-write operations or standard administrative tasks results in the system reporting that the resource is busy, despite no other processes appearing to hold the volume open.
For users with expensive storage hardware tied to these older formats, the situation presents a significant hurdle. One reported workaround involves a destructive process: deleting the logical volumes within a group and rebooting the machine to clear the "busy" state, which then allows the physical volume to be erased. However, this requires a complete wipe of the data. Because the system prevents in-place conversion to APFS, users who wish to keep their data are often forced to rebuild their storage configurations from backups. It remains unclear whether this total loss of support is a deliberate architectural removal or a software regression, as some users noted a potentially misleading boot dialog that references a future version of macOS rather than the current one.
This development highlights a growing gap for users maintaining legacy storage. While the transition to APFS is the standard path forward, the inability to use the system's own conversion tools means that older, encrypted HFS+ volumes are becoming "dead" assets on the new operating system. Until a more stable workaround or official support is restored, these volumes remain largely unusable for active data management on macOS 27.
This official image provides context for the new operating system version mentioned throughout the article.