In future releases of macOS, Mac users will no longer be able to format or eject disk images using the very long-standing Terminal command, hdiutil. It won’t affect many users directly, but it could well break disk repair utility apps.
You may never have even heard of it, but since the earliest days of Mac OS X, the Terminal has included the command now called hdiutil. It’s a tool for handling disk images, and AppleInsider forum users have often recommended it for solving problems such as the Mac refusing to eject such disk images because they’re purportedly in use.
As first spotted by developer Jeff Johnson, however, Apple is officially deprecating hdultil in macOS Golden Gate. What this means is that you, and app utilities, can continue using it for now, but should switch to the similar diskutil image command as ultimately hdiutil will be removed.
The command is on notice, meaning that it will be completely stripped out of macOS, but not in macOS Golden Gate. It may not even be removed in the next version of macOS, but it is going.
Typing man hdiutil into the Terminal app gets you a comprehensive manual about how to use the function, but as of the beta versions of macOS Golden Gate, the instructions are headed with a caution.
In macOS 27.0, hdiutil is deprecated. Use diskutil image instead for all disk image operations. diskutil image provides subcommands for attach, create, resize, info, and chpass. ASIF (Apple Sparse Image Format) images are only supported by diskutil image and are not supported by hdiutil.
Apple’s diskutil image tool currently duplicates most but not all of the functions in hdiutil. The now-preferred tool also operates differently, and this can be significant.
According to Johnson, using hdiutil as part of a backup process triggers an authentication prompt if a file is owned by the root user instead of the currently logged-in one. By comparison, diskutil image does not prompt for authentication, it simply fails with a generic error message.
It’s possible that the change is for security reasons. On October 15, 2025, Apple released a security update because of a bug in macOS Sonoma where “running an hdiutil command may unexpectedly execute arbitrary code.”
Apple further said that this issue “was addressed by removing the vulnerable code.” So the unspecified command was seemingly not replaced, it was solely removed.
What happens next
This change is not going to affect or even be noticed by the incredibly vast majority of Mac users. However, it’s not only people who know of the tool and use it Terminal who will be affected.
Instead, it’s also going to affect users of apps that call hdiutil in the background. Johnson mentions having worked on one such app that will simply fail to work once it is removed.
Typically the kinds of apps that use hdiutil, however, are disk repair and utility ones. And the developers of these will be familiar with Apple changing what they can do, so they will hopefully update before hdiutil is removed completely,
As of now, Apple’s only note about something not being possible in hdiutil in macOS Golden Gate is the one in the caution about Apple Sparse Image Format (ASIF). It’s not clear why Apple singles this out, however, as this feature has always been exclusive to diskutil image.
But now that hdiutil has been officially deprecated, it will be removed in a future version of macOS.
This change follows the 2025 deprecation of the Apple Filing Protocol in macOS Sequoia 15.5.