How to fix image data corrupted mac

The data in a disk image can be corrupted if a problem occurs while it’s being copied or if someone modifies it. You can see whether a disk image’s data has been corrupted by verifying its checksum, which is a calculation of all of its data. When a disk image is created, a checksum is computed and stored with the image. When you open the disk image, a checksum can be computed again and checked against the stored checksum. If the two checksums match, the disk image’s data hasn’t been corrupted.

You can choose when to compute and verify checksums. Be aware that doing so can take a long time.

Open Disk Utility for me

Please don’t include any personal information in your comment.

Maximum character limit is 250.

Thanks for your feedback.

A DMG file is a proprietary disk image file format developed by Apple for its Macintosh line of computers. These are large, single files that comprise the entirety of a physical disk, such as a DVD or CD, and, just like a real disk, they can be damaged and made inaccessible. While the causes of the damage can differ, Apple offers a built-in tool to repair DMG files on its Macs, and other companies have developed their own repair kits.

What is a DMG File?

1. A DMG file is used to copy the entirety of a disk or a drive into a single location while keeping some properties of that disk. This means that a DMG file created from a program’s installation disk will still allow you to install that program. Apple created the DMG file format, so it is typically supported by Mac computers, though some Windows and Linux programs also support DMG files. One benefit of a DMG file over a physical disk is the ability to password-protect the file so that you can restrict access to it.

Possible Damages

1. Since a DMG file is often created from a disk itself, scratches and damage to the disc being used can actually lead to a damaged file that has problems opening. When opening a DMG file, your computer treats it as if it were a physical disk, so problems your PC has opening media will cause issues when mounting the file. If the DMG file is stored somewhere else, like on a USB hard drive, unplugging the drive without first unmounting the DMG file can corrupt the part of the file that tells your computer how to open it.

Mac’s Built-In Repair Shop

1. Macs come with an application that can often fix issues related to DMG files, especially those caused by corrupt instructions for mounting a disk image. Open up your Applications folder, and click “Utilities.” Open up the Disk Utility application in that list to have access to the repair tool. Now simply drag your damaged DMG file onto the Disk Utility window. Click the damaged file, and then select “Repair Disk” in the First Aid tab. The service will then try to repair your file.

Getting Permission

1. Another possible way to repair a DMG file is to restore your access to it. Sometimes DMG files have their own installer that can restrict permissions to files within the DMG or even within the installation process used by Macs. In Disk Utility, there is also a “Repair Disk Permissions” feature that can restore your native permission and often helps users access DMG files where the installer was blocked. Open the Disk Utility and click the "First Aid" tab. Click your hard drive and then click "Repair Disk Permissions." If the DMG will successfully mount but not open, click it next in the Utility and then click the "Repair Disk Permissions" button for this as well.

2. 1. Public
   2. Questions

3. 1. Teams

      Stack Overflow for Teams – Start collaborating and sharing organizational knowledge. Create a free Team Why Teams?

   2. Teams

Stack Overflow for Teams is moving to its own domain! When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com.

Check your email for updates.

Asked 4 years, 2 months ago

Viewed 12k times

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?

• macos
• mac
• data-recovery
• macbook
• dmg-image

redbeam_

5375 silver badges16 bronze badges

asked Aug 30, 2018 at 10:36

Mahesh CheliyaMahesh Cheliya

791 gold badge1 silver badge6 bronze badges

12

• Do you have any idea what might've happened to it? What all has happened to it between when you created it and now?

  Aug 31, 2018 at 18:35

• @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.

  Sep 1, 2018 at 6:09

• @harrymc yes, if i try to open file in safe mode, it is display above message

  Sep 8, 2018 at 11:56

• 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.

  Apr 2, 2019 at 17:04

1 Answer

Found this online. Here is the link: How to repair a corrupted sparse bundle/image or dmg file

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)

Greenonline

2,0858 gold badges21 silver badges29 bronze badges

answered Sep 4, 2018 at 18:24

4

• Thanks for your answer! I tried first command but it gives this error "hdiutil: attach failed - Operation not permitted"

  Sep 5, 2018 at 9:21

• Use the term sudo before the command in order to elevate permissions

  Sep 10, 2018 at 15:52

• 'sudo' not working

  Sep 16, 2018 at 6:58

• It should be hdiutil attach -nomount -noverify -noautofsck -readwrite , i.e. hdiutil attach -nomount -noverify -noautofsck -readwrite ~/Downloads/image.dmg. The /Volumes (note not /volumes) is a total red herring. Also the error in the video is different "no mountable file systems", which is not the same issue as the OP has. It just goes to show that you shouldn't copy information from a youtube video without actually testing the commands....

  May 6 at 7:23

• The Overflow Blog
• Featured on Meta

Linked

Related

Hot Network Questions

• Simple Boolean Algebra Calculator
• Ethics: What is the principle which advocates for individual behaviour based upon the consequences of group adoption of that same behaviour?
• Count occurences of number in list of lists
• Can a Soulknife Harengon add a Psionic Energy Die to Initiative Checks?
• British 80s TV series about a toy soldier played by a real actor
• 1 picture of 4 not completely aligned
• There's an expect.php file in all the git repositories of my web server, is this malicious?
• Was J.R.R. Tolkien a fan of the original Star Trek series?
• Why do people say that Grover's algorithm does not parallelize well?
• Cannot switch to bash from zsh
• System.JSONException: Illegal value for primitive
• The Curé of Ars on Dancing
• How many creatures fit on a Carpet of Flying during combat?
• Can the trombone be played left-handed?
• What would prohibit replacing six 1.5V AA cells with a number of parallel wired 9V cells?
• Why consume DRIED apricots within 21 days?
• tikz - diagonal lines between nodes
• "Prime" pyramid
• How do you name the phenomenon of being single at a late age?
• Why do government employees pay income taxes?
• Creating a round bowl shape with wavy edge
• On the statistical meaning of density of states (DOS)
• CountourPlot3D wrong plotting result with extra surfaces
• Background replacement where Subject is leaned against the greenscreen and photographed at an angle?

more hot questions

Question feed

Your privacy

By clicking “Accept all cookies”, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.

How do I fix corrupted photos on my Mac?

How do you fix a corrupted disk on a Mac?

What does image corrupted mean?

How do I recover DMG files on Mac?