DMGs with license agreement fail to mount onto some Sonoma installations

Some of my users report a failure during mounting a DMG onto Sonoma created by DropDMG.

You find the complete thread here:

Any idea?

P.S: I use the latest DropDMG release version.

There’s a bug in macOS 14.0 that can cause this error (“The disk image couldn’t be opened. The operation couldn’t be completed. Permission denied.”) when mounting a disk image (FB13165607). It seems to only affect disk images that have license agreements and quarantine flags, and even then it does not happen on all Macs. It affects both disk images created with DropDMG and other tools. Some known workarounds:

  • Temporarily stop using a license agreement
  • Remove the xattr from the .dmg file after download
  • Download the disk image using a tool (e.g. curl) that does not add the quarantine attribute
  • Give the DiskImageMounter process Full Disk Access
  • Update to macOS 14.1 (beta), which seems to fix this bug

Apple fixed this bug in macOS 14.1, but I’m seeing a similar issue with macOS 14.4 Developer Beta 1. In this case, the workarounds above do not work, but the disk image can be mounted using hdiutil mount in Terminal or using DropDMG. I have filed bug number FB13570465 with Apple, and another developer has filed it as FB13569214.

When I updated to Sonoma 14.4 I could no longer mount my disk images. They have the license, created with DropDMG. I don’t get any error message. There is a crash report from diskImageMounter in the log files. I must remove license to work around. Added Note: disk images from my archives, that I created months ago, that worked previously, do not mount on the 14.4 machine. I have a 14.3 still works. I have not had a report of problem from users. Crash happens to both fresh disk image created local then tested, and disk images after download from our web site. I will drop license agreement immediately

I don’t think this will affect users because it only applies to the macOS 14.4 beta, and Apple says the bug is fixed in the next beta. You can mount the disk images on your Mac using DropDMG or hdiutil.

I put out a new Easy Data Transform release recently and got a couple of reports of this issue on macOS 14.4 beta. My DMG includes licensing text. I do hope Apple fix it for the production release.

Although not in the release notes, the bug seems to be fixed in macOS 14.4 Developer Beta 2.

Cool. Thanks Michael. I’ve been using DropDMG for years on several products and it has been very reliable.

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