Can’t open .dmg or .zip files – “DiskImageMounter/Archive Utility can’t be opened” (-36 error) MacOs

It is worth testing in a new user account, to determine if the problem is limited to your own account (it probably is).

It is also worth testing this in your own account, when booted in Safe Mode.

If it works, it will be a confirmation that some third party software that is running when you log in is causing the problem.

Please run Etrecheck and post its full report here. Use the "additional text" button and paste the report into the text box.

Actually, the file is fine, and this is a new bug in Sequoia.

It worked fine pre- 15.4.

Here's what I've found;

I've had a bunch of DiskImageMounter problems, and I found the bug, just not the fix.

I have several DMG's I've downloaded, and on another system, like Monterey, they work fine.

If I convert the images, they work fine, so I thought I was getting closer, and they were corrupt, but I was off, the DMGs are fine.

If I copy the downloaded images from my downloads folder, which is on another physical drive, to the desktop, they mount just fine. Then if I copy them back to my downloads folder, replacing the file(s) I just copied, they work fine. Again, nothing wrong with the DMG files, this is Sequoia.

I have used spctl and re-enabled, then disabled "allow anywhere", but it still will not open downloaded images, and gives an error 150, in DiskImageMounter, even though Disk Utility mounts them fine. Until I either convert the images, or copy back and forth to another location as above.

Nothing shows in the console.

This 100% is a new bug in Sequoia. I m not sure of which revision caused it, but I'm thinking around 15.4. This is a new problem.

From a very similar question with a very similar issue

And yes I did make an appearance in that question

The application “Installer” can’t be open… - Apple Community

Mine is giving error 150, not 36, but try my above solution and see if it works.

It's definitely a new macOS bug since 15.4

When I move my file(s) from my downloads folder to my desktop, then back, it fixes those file(s). In my case, they are physically two different drives.

There's no change to the file, no corruption, and MD5 is still the same.

It's a macOS problem, and I have Gatekeeper disabled.

Oh, also, I did try to touch the file in terminal, to see if that triggered anything, but it did not. It sill errors, and won't open until it's moved back and forth.

👍🏼

Fred_Leonard wrote:

Actually, the file is fine, and this is a new bug in Sequoia.

It worked fine pre- 15.4.

Here's what I've found;

From a link provided earlier

" To get the Full Installer of Sequoia 15.5

We used to be able to run the below Terminal command

softwareupdate --fetch-full-installer --full-installer-version 15.5

Caveat - Once the computer has Already installed Sequoia 15.4 and above

The above command will present as in illustration below

There has been a long discussion as to whether this is by Apple Design or an oversight

So far, there is very little information available, to confirm or refute these claims

So, in effect what you have tried to perform seems to confirm even the Pkg Installer of Sequoia is also affected by this negatively

Yes, we can see the currently available Full Versions of Sequoia

To reiterate, once Sequoia 15.4 is installed, downloading full versions thereafter seems problematic

softwareupdate --list-full-installers

Finding available software

Software Update found the following full installers:

* Title: macOS Sequoia, Version: 15.5, Size: 15283299KiB, Build: 24F74,

* Title: macOS Sequoia, Version: 15.4.1, Size: 15244333KiB, Build: 24E263,

* Title: macOS Sequoia, Version: 15.4, Size: 15243957KiB, Build: 24E248,

* Title: macOS Sequoia, Version: 15.3.2, Size: 14890483KiB, Build: 24D81,

* Title: macOS Sequoia, Version: 15.3.1, Size: 14891477KiB, Build: 24D70,

* Title: macOS Sequoia, Version: 15.3, Size: 14889290KiB, Build: 24D60, "