Unable to open DMG files - "Corrupt Image"

macos mac data-recovery macbook dmg-image

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Found this online. Here is the link: https://www.youtube.com/watch?v=TggCS8q5yGE

Here are the commands:

hdiutil attach -nomount -noverify -noautofsck -readwrite /volumes/"name of your image"

fsck_hfs -drfy /dev/diskxsx  (x is your disk number)

hdiutil detach /dev/diskxsx  (x is your disk number)

11,674

Mahesh Cheliya

I have 5+ years of experience in the iPhone app development. I'll always do my best to develop a high-quality app.

Updated on September 18, 2022

Comments

Mahesh Cheliya over 1 year
I created a DMG file using Disk utility in Recovery Mode (File -> New Image -> Image from Folder).

I tried all the possible options from this question:
- extracting DMG using 7Zip - not working
- converting it to another format like ISO - not converting
- opening DMG using Disk Drill - not opening
- opening DMG using Data Rescue - not opening
Is there any way to extract the data from the corrupted DMG file?
- Gordon Davisson over 5 years
  
  Do you have any idea what might've happened to it? What all has happened to it between when you created it and now?
- Mahesh Cheliya over 5 years
  
  @GordonDavisson when i created image, Macbook display "Operation Successfully", that time i not got any error or any warning message. I created saveral .dmg files like this, small files are opening without any issue, but Big size (Approx more than 2 GB) file is not opening.
- harrymc over 5 years
  
  Does that happen if you create and open the file when you Start up in safe mode ?
- Mahesh Cheliya over 5 years
  
  @harrymc yes, if i try to open file in safe mode, it is display above message
- harrymc about 5 years
  
  Try using Disk Utility by dragging the damaged DMG file onto its window, click the file and select “Repair Disk” in the First Aid tab. You could also try the free utility Disk Drill, recommended in such cases.
- Mahesh Cheliya about 5 years
  
  Hi @harrymc, I already tried it early and I also mentioned it in question. But unfortunately, I was not able to recover that file.
- harrymc about 5 years
  
  The DMG might be too damaged.
- Mahesh Cheliya about 5 years
  
  @harrymc I don't know why apple system generated corrupt dmg file because small files are open without any issue but large file gives an error message, and interestingly, I generated all files the same way.
- harrymc about 5 years
  
  How much large? Don't you have a reason-code associated with the error? Try also temporarily to disable checksum verification by the command defaults write com.apple.frameworks.diskimages skip-verify -bool true (undo if it doesn't help).
- Mahesh Cheliya about 5 years
  
  It's approx. more than 3 GB file. Let me try to use this command
- Mahesh Cheliya about 5 years
  
  I tried the skip-verify command, but it doesn't work.
- harrymc about 5 years
  
  It's then not a checksum problem. If size matters, then this relates probably to your method of creating the DMG.
Mahesh Cheliya over 5 years

Thanks for your answer! I tried first command but it gives this error "hdiutil: attach failed - Operation not permitted"
var firstName over 5 years

Use the term sudo before the command in order to elevate permissions
Mahesh Cheliya over 5 years

'sudo' not working