How to Download a macOS Disk Image
If you want to backup your data, save space, or create a bootable installer for macOS, you might need to download a macOS disk image. A disk image is a file that contains other files and folders, and it can be used for various purposes. In this article, we will show you how to download a macOS disk image using different methods.
What is a macOS Disk Image?
A macOS disk image is an exact copy of a disk or a partition. It can be used for backup purposes or to save space by storing only one copy of large files that are used infrequently. Disk images come in many formats, so they can be used on different kinds of computers, including Windows, macOS, and Linux. On macOS, the format of the disk image is .dmg.
download a macos disk image
Some benefits of using disk images are:
They can protect your data from loss or corruption.
They can compress your data and reduce the storage space needed.
They can encrypt your data and prevent unauthorized access.
They can create bootable installers for macOS or other operating systems.
How to Create a Blank Disk Image for Storage
You can create an empty disk image, add data to it, then use it to create disks, CDs, or DVDs. Here are the steps to create a blank disk image for storage using Disk Utility:
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.
In the Name field, enter the name for the disk image.
In the Size field, enter a size for the disk image.
Click the Format pop-up menu, then choose the format for the disk. For example, if you want to use the disk image with a Mac that has macOS 10.13 or later, choose APFS or APFS (Case-sensitive).
To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.
Click the Partitions pop-up menu, then choose a partition layout.
Click the Image Format pop-up menu, then choose an option. For example, if you want an expandable file that shrinks and grows as needed, choose Sparse disk image.
Click Save, then click Done.
Disk Utility creates the disk image file where you saved it in the Finder and mounts its disk icon on your desktop and in the Finder sidebar. In the Finder, copy your files to the mounted disk image, then eject it. You can then restore the disk image to another volume.
How to Create a Disk Image from a Disk or Connected Device
You can create a disk image that includes the data and free space on a physical disk or connected device, such as a USB device. For example, if a USB device or volume is 80 GB with 10 GB of data, the disk image will be 80 GB in size and include data and free space. You can then restore that disk image to another volume. Here are the steps to create a disk image from a disk or connected device using Disk Utility:
In the Disk Utility app on your Mac, choose File > New Image > Image from [device].
Select the device or volume in the dialog that appears, then click Open.
Enter a filename for the disk image, add tags if necessary, then choose where to save it.
To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.
Click the Image Format pop-up menu, then choose an option. For example, if you want a single file that can be compressed, choose Compressed.
Click Save, then click Done.
Disk Utility creates the disk image file where you saved it in the Finder. You can then restore the disk image to another volume.
How to Create a Bootable Installer for macOS
You can create a bootable installer for macOS using a macOS installer app that you can download from the App Store. A bootable installer is a disk image that contains everything you need to install macOS on your Mac or another Mac. You can use a bootable installer to upgrade your Mac, reinstall macOS, or install macOS on multiple Macs without downloading the installer each time. Here are the steps to create a bootable installer for macOS using Terminal:
Download the macOS installer app from the App Store. Make sure that it is in your Applications folder.
Connect a USB flash drive or other external drive that has at least 12 GB of available space and is formatted as Mac OS Extended (Journaled). Note the name of your drive, such as /dev/disk2.
Open Terminal, which is in the Utilities folder of your Applications folder.
Type or paste one of the following commands in Terminal. These commands assume that the installer is in your Applications folder and the name of your drive is /dev/disk2. Replace /dev/disk2 with the correct name of your drive. Be careful to use the correct name, as this process will erase the drive.
For macOS Monterey: sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For macOS Big Sur: sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For macOS Catalina: sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For macOS Mojave: sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
For macOS High Sierra: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
Press Return after typing the command.
When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Monterey. You can now quit Terminal and eject the volume.
Conclusion
In this article, we have shown you how to download a macOS disk image using different methods. You can create a blank disk image for storage, a disk image from a disk or connected device, or a bootable installer for macOS. Depending on your needs and preferences, you can choose the best method for you. We hope this article was helpful and informative. If you have any questions or feedback, please let us know in the comments below.
How to download macOS disk image from Apple Support[^1^]
Create a bootable installer for macOS using a disk image[^2^]
How to get macOS Big Sur as a DMG file[^3^]
Download macOS Catalina disk image and create a bootable USB
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Download macOS Monterey disk image and install it on your Mac
How to create a macOS disk image backup using Disk Utility
Download macOS High Sierra disk image and upgrade your Mac
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Download macOS Mojave disk image and clean install it on your Mac
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Download macOS El Capitan disk image and reinstall macOS on your Mac
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Download macOS Mountain Lion disk image and update your Mac
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Download macOS Yosemite disk image and dual boot with Windows
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Download OS X Mavericks disk image and downgrade your Mac
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FAQs
Here are some frequently asked questions and answers about downloading a macOS disk image:
Q: How do I open a disk image on my Mac?
A: To open a disk image on your Mac, double-click it in the Finder. The disk image mounts and its icon appears on your desktop and in the Finder sidebar. You can then access its contents like any other disk.
Q: How do I burn a disk image to a CD or DVD on my Mac?
A: To burn a disk image to a CD or DVD on your Mac, insert a blank disc into your optical drive and select it in the Finder sidebar. Then drag and drop the disk image file onto the disc icon. Alternatively, you can right-click or Control-click the disk image file and choose Burn Disk Image [name] to Disc from the shortcut menu.
Q: How do I use a bootable installer to install macOS on my Mac?
A: To use a bootable installer to install macOS on my Mac, I need to connect the USB flash drive or other external drive that contains the bootable installer to my Mac. Then I need to restart my Mac and hold down the Option key while it starts up. I will see a list of startup disks, including the bootable installer. I need to select the bootable installer and click Continue. Then I will see the macOS Utilities window, where I can choose to install macOS, restore from a Time Machine backup, or use other utilities.
Q: How do I verify the integrity of a disk image on my Mac?
A: To verify the integrity of a disk image on my Mac, I can use Disk Utility or Terminal. In Disk Utility, I can select the disk image file in the sidebar and click the First Aid button in the toolbar. Disk Utility will check the disk image for errors and repair them if possible. In Terminal, I can use the hdiutil command with the verify option to check the disk image for errors. For example, to verify a disk image named MyImage.dmg, I can type: hdiutil verify MyImage.dmg
Q: How do I convert a disk image to a different format on my Mac?
A: To convert a disk image to a different format on my Mac, I can use Disk Utility or Terminal. In Disk Utility, I can choose File > New Image > Image from [file], then select the disk image file that I want to convert. In the dialog that appears, I can click the Image Format pop-up menu and choose a different format, such as read/write or compressed. Then I can click Save to create a new disk image file with the chosen format. In Terminal, I can use the hdiutil command with the convert option to change the format of a disk image. For example, to convert a disk image named MyImage.dmg to a compressed format, I can type: hdiutil convert MyImage.dmg -format UDZO -o MyImageCompressed.dmg 44f88ac181
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