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I've created a .dmg using Disk Utility from a 32 GB source drive. Now I'm back in Disk Utility in order to restore this disk image to the very same source disk it was created from. I thought it would be a simple operation, but I can't seem to wrap my head around it.

What I've tried:

  • Restoring to the drive in Disk Utility and selecting the .dmg as source. I get an error every time: Image needs to be scanned. Will restore as mounted disk image. Operation failed… No definition of "scanned" is provided. I have verified the image successfully.
  • Mounting the .dmg and restoring using its device as the source. Now I get another error: The operation couldn’t be completed. (OSStatus error 6.) Operation failed… It also mentions that some volumes are not Apple_HFS or Apple_UFS, which seems entirely irrelevant to me since I'm not trying to restore a specific volume.

What makes me even more confused is when I then read an Apple's support article, which states:

To restore a disk image with multiple volumes to a disk, you must partition the destination disk, then restore each volume individually

This makes no sense to me. I'm working under the assumption that a "disk image" is, well, a disk image. The partition table — a piece of data that resides on the disk — has to be recreated in order to restore a disk image? That's a contradiction to me. What is going on here?

Anyway, I tried what the article suggested as well:

  • Erased the destination device and created a new APFS volume. Selected this empty volume and restored to it from the mounted dmg's APFS volume. It looks like it's working, but I return later to some error "OSStatus -119930872". I don't know how to interpret that.

At this point I felt like I've misunderstood something fundamental, so I ask here.

How am I supposed to restore a disk image to the very disk it is an image of? How am I supposed to figure out the right way to do it?

MacOS 10.14.6

Most Disk Utility output can't be provided. I changed system language to English, but the application disregards it after reboot.

Update

Output of hdiutil imageinfo <file>.dmg:

nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
nx_kernel_mount:1473: : checkpoint search: largest xid 10149, best xid 10149 @ 109
Format Description: UDIF read-only
Class Name: CUDIFDiskImage
Checksum Type: CRC32
Size Information:
    Compressed Ratio: 1
    Total Empty Bytes: 6233303552
    Sector Count: 62533296
    Total Bytes: 32017047552
    CUDIFEncoding-bytes-wasted: 0
    Total Non-Empty Bytes: 25783744000
    CUDIFEncoding-bytes-in-use: 25783744000
    Compressed Bytes: 25783744000
    CUDIFEncoding-bytes-total: 25783744000
Checksum Value: $B3A0A719
Segments:
    0: /path/to/SanDisk Extreme Media.dmg
Partition Information:
    7:
        Name: GPT Header (Backup GPT Header : 8)
        Partition Number: 7
        Checksum Type: CRC32
        Checksum Value: $4C182713
    3:
        Name: EFI System Partition (C12A7328-F81F-11D2-BA4B-00A0C93EC93B : 4)
        Partition Number: 3
        Checksum Type: CRC32
        Checksum Value: $E6D2A8FA
    4:
        Name: <VolumeName> (Apple_APFS : 5)
        Partition Number: 4
        Checksum Type: CRC32
        Checksum Value: $08B05B86
    0:
        Name: GPT Header (Primary GPT Header : 1)
        Partition Number: 0
        Checksum Type: CRC32
        Checksum Value: $551B4391
    5:
        Name:  (Apple_Free : 6)
        Partition Number: 5
        Checksum Type: CRC32
        Checksum Value: $00000000
    1:
        Name: GPT Partition Data (Primary GPT Table : 2)
        Partition Number: 1
        Checksum Type: CRC32
        Checksum Value: $69E12033
    6:
        Name: GPT Partition Data (Backup GPT Table : 7)
        Partition Number: 6
        Checksum Type: CRC32
        Checksum Value: $69E12033
    -1:
        Name: Protective Master Boot Record (MBR : 0)
        Partition Number: -1
        Checksum Type: CRC32
        Checksum Value: $4FBC01BD
    2:
        Name:  (Apple_Free : 3)
        Partition Number: 2
        Checksum Type: CRC32
        Checksum Value: $00000000
Format: UDRO
Backing Store Information:
    URL: file:///path/to/SanDisk%20Extreme%20Media.dmg
    Name: SanDisk Extreme Media.dmg
    Class Name: CUDIFEncoding
    Backing Store Information:
        URL: file:///path/to/SanDisk%20Extreme%20Media.dmg
        Name: SanDisk Extreme Media.dmg
        Class Name: CBSDBackingStore
partitions:
    partition-scheme: GUID
    block-size: 512
    partitions:
        0:
            partition-name: Protective Master Boot Record
            partition-start: 0
            partition-synthesized: true
            partition-length: 1
            partition-hint: MBR
        1:
            partition-name: GPT Header
            partition-start: 1
            partition-synthesized: true
            partition-length: 1
            partition-hint: Primary GPT Header
        2:
            partition-name: GPT Partition Data
            partition-start: 2
            partition-synthesized: true
            partition-length: 32
            partition-hint: Primary GPT Table
        3:
            partition-name: 
            partition-start: 34
            partition-synthesized: true
            partition-length: 6
            partition-hint: Apple_Free
        4:
            partition-UUID: AE491320-617A-49C4-8885-4727B6C9E238
            partition-name: EFI System Partition
            partition-hint-UUID: C12A7328-F81F-11D2-BA4B-00A0C93EC93B
            partition-start: 40
            partition-number: 1
            partition-length: 409600
            partition-hint: C12A7328-F81F-11D2-BA4B-00A0C93EC93B
            partition-filesystems:
                FAT32: EFI
        5:
            partition-UUID: AA9B39E4-38A7-4456-9DD8-FBA36B123EE0
            partition-name: <VolumeName>
            partition-hint-UUID: 7C3457EF-0000-11AA-AA11-00306543ECAC
            partition-start: 409640
            partition-number: 2
            partition-length: 62123616
            partition-hint: Apple_APFS
            partition-filesystems:
                APFS: Untitled
        6:
            partition-name: 
            partition-start: 62533256
            partition-synthesized: true
            partition-length: 7
            partition-hint: Apple_Free
        7:
            partition-name: GPT Partition Data
            partition-start: 62533263
            partition-synthesized: true
            partition-length: 32
            partition-hint: Backup GPT Table
        8:
            partition-name: GPT Header
            partition-start: 62533295
            partition-synthesized: true
            partition-length: 1
            partition-hint: Backup GPT Header
    burnable: false
udif-ordered-chunks: true
Properties:
    Encrypted: false
    Kernel Compatible: true
    Checksummed: true
    Software License Agreement: false
    Partitioned: false
    Compressed: false
Resize limits (per hdiutil resize -limits):
 min     cur     max 
62533296    62533296    62533296
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2
  • What's the result of hdiutil imageinfo /path/to/image.dmg? – klanomath Feb 7 '20 at 21:46
  • @klanomath I updated the question with the output – Andreas Feb 7 '20 at 23:33
1

If I remember correctly, you need to create a checksum as detailed in this Apple Help document before you can restore to another disk.

  • In the Disk Utility app on your Mac, choose Images > Add Checksum, then select the disk image to add the checksum to.

  • Click Open, then click Done.

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4
  • Operation not permitted Operation failed… -- It's a read only image so I guess that's to be expected – Andreas Feb 8 '20 at 13:31
  • Does Checksummed: true in the output of hdiutil not suffice? – Andreas Feb 8 '20 at 13:35
  • I don’t know. Does the checksum command exist in the DiskUtility interface? (I’m on an iPad at the moment and can’t check my Mojave iMac.) If the command exists, and you haven’t run it, give it a try. – IconDaemon Feb 8 '20 at 14:16
  • Yes, it exists. It gives that exact output. – Andreas Feb 8 '20 at 14:17

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