Diskimagemounter

Is normally found in the Utilities Folder/which is in applications right? And does the computer,that I copy off of, have to be the exact version as mine which is btw MAC OSX 10.2. Disk image mounter; disk image mounter windows 10; Diskimagemountermacosx Os X Disk Image; Mac Os Disk Image Download; Mac Os X Iso For. Big Sur DiskImageMounter.app weirdness with network read/write.dmg 4 posts oldseeker. Wise, Aged Ars Veteran et Subscriptor. Registered: Jan 17, 2008. Posted: Sat May 08, 2021 5:44 pm.

I have an Airport Extreme with a USB port that's my home router and WiFi. My Mac is normally connected by Ethernet. I put an older 8GB flash drive in the Airport USB port, which I use as a cache backup for small high-value data so I can make a quick copy off-Mac without spinning up my usual backup disk (USB on my Mac). I also like that it's nearly hidden, in another room.
The flash drive has only two files: An encrypted .dmg, created read/write, 200 MB, and a readme file. When I want to do this quicky backup, I use Finder to mount the flash drive (a few seconds, the password is in my Keychain) and then mount the .dmg, maybe a little longer (The .dmg password is also in my Keychain). Then copy the data of interest to the .dmg, maybe delete something older, eject the .dmg, and then eject the flash drive. This has worked reliably since 2013, predating my current Airport installed in 2018.
Since upgrading to Big Sur (I waited until 11.2) the .dmg mount using either double-click, invoking DiskImageMounter.app, or choosing it from the context menu, fails. There's a progress popup 'Verifying AirPortDisk.dmg ...' which consistently fails after a few seconds with a popup “AirPortDisk.dmg” is damaged and can’t be opened. You should eject the disk.'. That has a '?' button, and clicking that tells me 'The app has been modified or damaged. The app has been modified, and its code does not match the original signed code. The app may be broken or corrupted, or it may have been tampered with. ...' along with some other irrelevant noise about security preferences that I could not relate to this context.
If I plug the flash drive into a USB hub connected to my Mac, DiskImageMounter.app mounts the .dmg without a problem.
If I use Finder to simply copy the .dmg from the Airport-mounted flash drive to the Desktop, then double-click on the copy, DiskImageMounter.app mounts it successfully.
Search found me the Terminal commands:

A modification of this answer can be used for ssh keys on an external FAT or ExFAT drive (e.g. Mounted via VeraCrypt or whatever). Add the following line to your /etc/fstab file, even if it doesn't exist: LABEL=PRIVATE none msdos -u=501,-m=700. This assumes your user ID is 501 (try ls -n ) and the label on your FAT or ExFAT volume is PRIVATE. ファイルを右クリックし、このアプリケーションで開く DiskImageMounterを選択します。 注意：正常な動作のためにはサードパーティ製ツールではなく、AppleのDiskImageMounterを使用することが重要です。 ディスクイメージが仮想ドライブとしてマウントされます。.

This mounts the .dmg directly from the Airport flash drive without complaint.
I looked at the man page for hdiutil to see if I would learn something, and found this under the 'verify' verb:
'... Read/write images don't contain checksums and thus can't be verified. ...', and sure enough,

I don't have any other NAS, so I can't tell if this is just Airport disk or a more general problem. So it seems to be some confused attempt to check a (nonexistent by design) signed code signature on my read/write data file .dmg, that only is incorrectly invoked using the GUI, and only on a network-mounted volume. But I don't know enough about whatever they did in Big Sur that's responsible, or more importantly, how to fix it. There are workarounds, but they are awkward, and this used to work.
I couldn't find anything related to this issue with internet search. Any idea from the community?

'Replaces the system default DMG mounting application; is better in every way.'
- Some Guy on the Internet

FastDMG is a free macOS utility to mount .dmg and other disk images quickly, without any unneeded nonsense. It is a very fast and reliable alternative to Apple's annoying DiskImageMounter. And yes, that icon is a reference to After Dark's Flying Toasters screensaver on Classic MacOS.

Features

• Doesn't waste your precious time verifying disk images
• Auto-accepts annoying end user license agreements
• Runs in the background (doesn't show up in the Dock)
• Displays no windows or menus and stays out of your way
• Multithreaded, can concurrently mount several images
• Disk image document icons continue to look the same
• Handles all disk image types supported by DiskImageMounter (dmg, iso, toast, etc.)

Diskimagemounter Cpu

FastDMG is actually a minimal wrapper around the hdiutil command line tool that ships with macOS and therefore uses Apple's private DiskImages framework indirectly.

I've personally used FastDMG for many years and it works really well. It's solid, free, open source software and has a home on GitHub. If you like it, feel free to make a donation.

Download

• ⇩ Download FastDMG 1.0.2 (~1.4 MB, Universal ARM/Intel 64-bit, 10.9 or later)

How to use

• Move FastDMG.app to your Applications folder
• Ctrl-click the FastDMG app and select Open to bypass Apple's Gatekeeper
• Select a .dmg file in the Finder and press Cmd-I to show the Get Info window
• Select FastDMG under 'Open with:'
• Press 'Change All...'

FastDMG will then take care of mounting .dmg disk images when they're opened in the Finder. You can do the same for .iso, .toast and any other disk images supported by FastDMG.

Diskimagemounter No Mountable File Systems

Version History

1.0.2 - 28/11/2020

Diskimagemounter Utility

• App is now built as a Universal ARM/Intel 64-bit binary

1.0.1 - 07/04/2019

• App is now Developer ID signed
• Now built with support for Mojave Dark Mode

1.0 - 23/05/2018

• Initial release