Apple Replaces hdiutil with diskutil image in macOS 27 Golden Gate

Apple has deprecated the hdiutil command-line tool in macOS 27.0 Golden Gate, directing users to diskutil image for all disk image operations. The deprecation notice appears at the top of the man hdiutil page on the Golden Gate beta, alongside a "WHAT'S NEW" section that spells out the replacement subcommands: attach, create, resize, info, and chpass. The man page also documents a deprecation table mapping existing hdiutil subcommands to their diskutil equivalents. (Lapcat Software)

For context, a disk image is a single file that contains the complete contents and structure of a disk or folder. On macOS, disk images typically use the .dmg format and are the standard way to distribute software. hdiutil has been the command-line tool for creating, mounting, and managing these images for years. diskutil is a broader disk management tool that already handles formatting partitions and other storage tasks; Apple is now folding disk-image operations into it.

diskutil image is not a one-to-one port. Several hdiutil options have no equivalent on the new tool. The -puppetstrings flag, long used for scripted progress reporting, is absent. On the creation side, a cluster of hdiutil create -srcfolder options is missing: crossdev, scrub, anyowners, skipunreadable, atomic, and copyuid. Scripts that depend on any of these flags will need revision before they can migrate.

There is also a behavioral difference around privilege. When creating a disk image that contains a file owned by the root user, hdiutil triggers an authentication prompt, allowing the operation to proceed with elevated privileges. diskutil does not prompt. Instead, it fails outright with an "Operation not permitted" error. Any automated workflow that relied on hdiutil's auth-prompt behavior will need an alternate elevation strategy, such as pre-authenticating via sudo or restructuring the image-creation pipeline to avoid root-owned source files.

Not everything about the migration is a regression. In a benchmark on macOS 27 Golden Gate, diskutil image create finished in roughly 40 to 45 seconds, compared with 110 to 115 seconds for hdiutil create on the same task. The resulting .dmg file was also smaller: 2.8 GB versus 2.89 GB. The performance gap is substantial enough that developers who can tolerate the missing options may find the switch worthwhile on speed alone.

One format detail stands out. ASIF (Apple Sparse Image Format) images are supported by diskutil image but not by hdiutil. A sparse image is one that grows as data is added rather than allocating its full size upfront. This suggests Apple's disk-image infrastructure has already shifted to diskutil internally for newer formats, with hdiutil lagging behind on the legacy side rather than serving as the reference implementation.

For developers and IT administrators, the practical impact is migration planning. Build scripts, CI pipelines (automated systems that compile and test code), and packaging tools that invoke hdiutil directly will continue to work while the tool remains present, but the deprecation notice is a clear signal that the window is closing. The missing options are the harder problem. A script using hdiutil create -srcfolder with scrub or atomic cannot simply swap the binary name; the underlying capability may need to be reimplemented at the shell level or replaced with a different workflow entirely. The auth-prompt difference adds another layer: any pipeline that handled privilege escalation implicitly through hdiutil's prompt will now encounter a silent failure unless it pre-elevates.

The performance improvement and ASIF support suggest Apple has been building diskutil image as the forward path for some time, not merely renaming a legacy tool. The broader context here is that deprecation notices from Apple tend to become removals within a few major releases. Developers who depend on disk-image automation in macOS environments should begin auditing their hdiutil usage now, cataloging which options and behaviors their scripts rely on, and testing diskutil image equivalents against those requirements before the deprecation window narrows further.