How To Create A Dmg Image Of An Imac

Learning how to create a bootable macOS installation disk can be helpful in a variety of situations. Rather than download and install a new OS from Apple's servers each time, it can be used for multiple installations on different machines. It can also help in situations where the operating system is corrupted or installation from app store shows errors.

To create a bootable macOS installation disk, you have to burn the DMG file to a USB drive as CD/DVD is not available for Mac computers. Here's how to do it from text commands and using a purpose-built software called WizDMG. You will first need to download the DMG file for the macOS version you wish to install. For example, if you want to create a bootable macOS Mojave installer, you will need the DMG file for macOS Mojave. Once the file has been downloaded to your PC, you can proceed with one of the bootable disk creation methods shown below.

This quick instruction will help any-one to make a Bootable MacOS Catalina Installer.ISO and.DMG images in MacOS and Windows. MacOS Catalina.ISO is needed for installing Catalina into a virtual machine using VMWare and Virtual box and other purposes. How to create a Bootable MacOS Catalina.ISO image on a Mac? Step 1: Download MacOS Catalina.app from App Store into Applications folder.

Method 1: How to Create Bootable USB Installer for Mac via Commands

macOS (formly named Mac OS X) is just a variant of popular Unix based operating system. This means a lot of daily and advanced tasks on Mac can be done via text commands such as creating bootable USB installer for Mac. However, this could be a lot of challenges if you had no clue about commands and I suggest taking a look at the other solutions in this post to avoid messing up the computer with the wrong commands.

Just drag and drop a file or folder, and DropDMG automatically figures out what to do: create a disk image, convert to another format, join files, etc. Deliver your Mac app on a.dmg file with a software license agreement, a custom volume icon, and a precise icon layout atop a Retina-optimized background. You can create an empty disk image, add data to it, then use it to create disks, CDs, or DVDs. In the Disk Utility app on your Mac, choose File New Image Blank Image. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

Step 1. Search macOS name in app store (Mojave, High Serria, EI Capitai). Click 'Get' button to download the installer image on your Mac. The downloaded file will be located in Application folder.

Step 2. When the download is completed, the installation windows opens automatically, just close the window and go to Application folder. You will find a file started Install, such as Install macOS Majave.

Step 3. Now connect an external flash drive with more than 16G free space. And backup the data in that USB drive as the installer erase all content from it. Open Disk Utility app and format the USB drive with APFS or Mac OS Extended.

Step 4. Open the Terminal app and copy-and-past the following commands to make a booatble USB installer from macOS image:
For Majove: sudo /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For High Serria: sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For EI Capitan: sudo /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install OS X El Capitan.app

Step 5. Input the admin password when being prompted. And wait for the booatable disk being created. When it is done successfully, you will receive a message shown in above screenshot.

Unconfortable with text commadns and prefer doing it in a simple way? The second suggestion is more user friendly!

Method 2: How to Make Bootable USB from macOS with WizDMG

WizDMG fills a huge gap in Windows not supporting DMG files. It is a desktop utility supporting Windows and Mac. It allows you to directly burn DMG files to disk in order to create a bootable macOS Mojave installer or a boot disk for any macOS version.

WizDMG offers an intuitive interface with no clutter and full functionality to handle DMG files. Apart from burning such disk image files to DVD/CD or USB, it also gives you edit options where you can add and remove files from within the DMG file, rename DMG files and even create DMGs from files and folders on your desktop. This software application has been created for novice users as well as experts. It is easy to use, has a very high burn success rate and will help you create a bootable macOS installer in no time. Follow the instructions below:

Step 1Install WizDMG

Download WizDMG from the official website and install it on your PC. Launch the program and select the 'Burn' option in the main interface.

Step 2Create Bootable USB from macOS Install Image

Click on Load DMG to import the macOS installation file into the application. Insert a USB (16G free space) and click on the 'Burn' button next to the appropriate media type.

The important thing to remember here is that you now know how to create a macOS installer in Windows. There aren't a lot of options out there because of the compatibility issues between Mac and Windows environments. That means converting DMG to ISO and back again to DMG leaves the door open for corrupted files and incorrectly burned bootable media, which defeats the whole purpose because it might not even work in the end.

Method 3: Create macOS High Serria/Mojave Bootable USB on Windows 10/7

Another way to create macoS bootable disk on Windows is using a tool called DMG2IMG along with Windows command prompt. It requires a bit of a workaround, but even novice users can learn to burn a DMG file to a disk to create bootable media for a macOS installation. Just make sure you follow the instructions below carefully.

Step 1. Download DMG2IMG and install it in your Windows PC. Open File Explorer and go to the folder containing the DMG2IMG program, then right-click and select 'Open command windows here.'

Step 2. Type the following command and hit Enter: dmg2img [sourcefile.dmg] [destinationfile.iso]

Step 3. Now that the DMG file has been converted to ISO format, you can use the following command to burn it to a disk. Before that, insert a disk into the optical drive: isoburn.exe /Q E: 'C:UsersUsernameDesktopdestinationfile.iso'

Step 4. This command utilizes the Windows native disk image burner to burn the ISO to the disk in your optical drive. The ISO file can't be used directly in macOS, but it can be mounted as a virtual drive. Once you do this, you can convert it back to DMG using Disk Utility in Mac. You can then use this as your bootable macOS installer.

As you can see, this is a bit of a workaround because DMG files aren't natively supported in Windows. Likewise, ISO files aren't fully supported in macOS. However, you can use this method to create a macOS installation disk in Windows. If you want a much simpler solution, then review the next method shown here.

Summary

If you ask us how to create a bootable macOS installation disk, this is the method we recommend. There's no confusing command line work involved, you don't need a bunch of additional software utilities to get the job done, and the high accuracy of the application ensures that you won't be wasting disk after disk trying to burn the installation media for macOS onto a disk. Use WizDMG as a quick and painless way to create a macOS installation disk in a very short time.

Nov 15, 2018 16:47:20. / Posted by Candie Kates to Mac Solution

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How To Create A Dmg Image Of An Imac Screen

Apple Disk Image
The icon represents an internal hard drive within a generic file icon.
Filename extension.dmg, .smi, .img
Internet media typeapplication/x-apple-diskimage
Uniform Type Identifier (UTI)com.apple.disk-image
com.apple.disk-image-smi
Developed byApple Inc.
Type of formatDisk image

Apple Disk Image is a disk image format commonly used by the macOS operating system. When opened, an Apple Disk Image is mounted as a volume within the Macintosh Finder.

An Apple Disk Image can be structured according to one of several proprietary disk image formats, including the Universal Disk Image Format (UDIF) and the New Disk Image Format (NDIF). An Apple disk image file's name usually has '.dmg' as its extension.

Features[edit]

Apple Disk Image files are published with a MIME type of application/x-apple-diskimage.

Different file systems can be contained inside these disk images, and there is also support for creating hybrid optical media images that contain multiple file systems.[1] Some of the file systems supported include Hierarchical File System (HFS), HFS Plus, File Allocation Table (FAT), ISO9660 and Universal Disk Format (UDF).[1][2]

How To Create A Dmg Image Of An Imac Computer

Apple Disk Images can be created using utilities bundled with Mac OS X, specifically Disk Copy in Mac OS X v10.2 and earlier and Disk Utility in Mac OS X v10.3 and later. These utilities can also use Apple disk image files as images for burning CDs and DVDs. Disk image files may also be managed via the command line interface using the hdiutil utility.[3]

In Mac OS X v10.2.3, Apple introduced Compressed Disk Images[4] and Internet-Enabled Disk Images for use with the Apple utility Disk Copy, which was later integrated into Disk Utility in 10.3. The Disk Copy application had the ability to display a multi-lingual software license agreement before mounting a disk image. The image will not be mounted unless the user indicates agreement with the license.[5]

An Apple Disk Image allows secure password protection as well as file compression, and hence serves both security and file distribution functions; such a disk image is most commonly used to distribute software over the Internet.

History[edit]

Apple originally created its disk image formats because the resource fork used by Mac applications could not easily be transferred over mixed networks such as those that make up the Internet. Even as the use of resource forks declined with Mac OS X, disk images remained the standard software distribution format. Disk images allow the distributor to control the Finder's presentation of the window, which is commonly used to instruct the user to copy the application to the correct folder.

How To Create A Dmg Image Of An Imac

A previous version of the format, intended only for floppy disk images, is usually referred to as 'Disk Copy 4.2' format, after the version of the Disk Copy utility that was used to handle these images.[1] A similar format that supported compression of floppy disk images is called DART.[1][6]

New Disk Image Format (NDIF) was the previous default disk image format in Mac OS 9,[1] and disk images with this format generally have a .img (not to be confused with raw .img disk image files) or .smi file extension. Files with the .smi extension are actually applications that mount an embedded disk image, thus a 'Self Mounting Image', and are intended only for Mac OS 9 and earlier.[7][2]

Universal Disk Image Format (UDIF) is the native disk image format for Mac OS X. Disk images in this format typically have a .dmg extension.[1]

File format[edit]

Apple has not released any documentation on the format, but attempts to reverse engineer parts of the format have been successful. The encrypted layer was reverse engineered in an implementation called VileFault[8] (a spoonerism of FileVault).

Apple disk image files are essentially raw disk images (i.e. contain block data) with some added metadata, optionally with one or two layers applied that provide compression and encryption. In hdiutil these layers are called CUDIFEncoding and CEncryptedEncoding.[1]

UDIF supports ADC (an old proprietary compression format by Apple), zlib, bzip2 (as of Mac OS X v10.4), and LZFSE (as of Mac OS X v10.11)[9] compression internally.

Trailer[edit]

The trailer can be described using the following C structure.[10] All values are big-endian (PowerPC byte ordering)

Here is an explanation:

Position(in Hex)Length (in bytes)Description
0004Magic bytes ('koly').
0044File version (current is 4)
0084The length of this header, in bytes. Should be 512.
00C4Flags.
0108Unknown.
0188Data fork offset (usually 0, beginning of file)
0208Size of data fork (usually up to the XMLOffset, below)
0288Resource fork offset, if any
0308Resource fork length, if any
0384Segment number. Usually 1, may be 0
03C4Segment count. Usually 1, may be 0
04016128-bit GUID identifier of segment
0504Data fork checksum type
0544Data fork checksum size
058128Data fork checksum
0D88Offset of XML property list in DMG, from beginning
0E08Length of XML property list
0E8120Reserved bytes
1604Master checksum type
1644Master checksum size
168128Master checksum
1E84Unknown, commonly 1
1EC8Size of DMG when expanded, in sectors
1F412Reserved bytes (zeroes)

Utilities[edit]

There are few options available to extract files or mount the proprietary Apple Disk Image format. Some cross-platform conversion utilities are:

  • dmg2img was originally written in Perl; however, the Perl version is no longer maintained, and the project was rewritten in C. Currently, without additional tools, the resulting images may be mounted only under Mac OS X and under Linux (provided hfsplus support has been enabled). UDIF ADC-compressed images have been supported since version 1.5.[11]
  • DMGEXtractor is written in Java with GUI, and it supports more advanced features of dmg including AES-128 encrypted images but not UDCO images.[12]
  • 7-Zip, including the free cross-platform port of its command-line interface, p7zip.

In Windows, most dmg images can be opened using several other programs such as UltraISO and IsoBuster. MacDrive can also mount simple dmg files as drives under windows, but not sparse disk or encrypted dmgs.[13] A free Apple DMG Disk Image Viewer also exists.[14]

In Linux and possibly other Unix flavors, most .dmg files can be burned to CD/DVD using any CD-burner program (using cdrecord directly or a front-end such as K3B or Brasero) or directly mounted to a mountpoint (e.g. mount -o loop,ro -t hfsplus imagefile.dmg /mnt/mountpoint).[15][16] darling-dmg is a FUSE module enabling easy DMG file mounting on Linux.[17]

How To Create A Dmg Image Of An Imac 2017

See also[edit]

References[edit]

  1. ^ abcdefg'hdiutil(1) Mac OS X Manual Page'. Archived from the original on 2016-05-14. Retrieved 2016-05-14.
  2. ^ ab'Mac OS X: Using Disk Copy disk image files'. Archived from the original on 2013-12-19. Retrieved 2013-04-25.
  3. ^hdiutil(1) – Darwin and macOS General Commands Manual
  4. ^'Re: Some apps refuse to launch in 10.2.8! (OT, but very important)'. Archived from the original on 2014-01-17.
  5. ^'Guides'. Apple. Archived from the original on 2009-03-06. Retrieved 2010-10-27.
  6. ^'DART 1.5.3: Version Change History'. Archived from the original on 2013-12-19. Retrieved 2013-04-25.
  7. ^'Software Downloads: Formats and Common Error Messages'. Archived from the original on 2010-12-24. Retrieved 2009-05-06.
  8. ^'VileFault'. 2006-12-29. Archived from the original on 2007-01-09. Retrieved 2010-10-27.
  9. ^Michael Tsai (2015-10-07). 'LZFSE Disk Images in El Capitan'. Archived from the original on 2017-04-09. Retrieved 2017-04-09.
  10. ^'Demystifying the DMG File Format'. Archived from the original on 2013-03-17.
  11. ^'dmg2img'. Archived from the original on 29 November 2010. Retrieved 2010-10-27.
  12. ^'DMGExtractor'. Archived from the original on 2011-01-02. Retrieved 2011-01-03.
  13. ^MacDrive Features / Boot Camp / System Requirements /. 'MacDrive Home page'. Mediafour. Archived from the original on 4 October 2010. Retrieved 2010-10-27.
  14. ^Olivia Dehaviland (2015-03-03). 'Apple DMG Disk Image Viewer'. DataForensics.org. Archived from the original on 2015-04-02. Retrieved 2015-03-10.
  15. ^'How To Convert DMG To ISO in Windows, Linux & Mac'. Archived from the original on 2010-03-07.
  16. ^'Convert DMG To ISO using PowerISO'. Archived from the original on 2009-05-02. Retrieved 2009-02-15.
  17. ^'darling-dmg'. darling-dmg. Retrieved 29 March 2015.

External links[edit]

Burn Dmg Image

  • Apple Developer Connection A Quick Look at PackageMaker and Installer
  • O'Reilly Mac DevCenter Tip 16-5. Create a Disk Image from a Directory in the Terminal

How To Create A Dmg Image Of An Imac Download

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