Create Encrypted Dmg File Mac

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Disk Utility User Guide

Unmounting an encrypted disk image returns the image file to an encrypted state, preventing access to the data stored within. You can unmount the image by dragging the mounted image (not the image file) to the trash, or right-clicking on the mounted image and selecting Eject from the popup menu.

  1. This will create a new dmg file which will be password-protected. This will leave only the encrypted DMG behind. Related: How to Fully Secure Your Mac with These 9 Steps. Using Encrypto. Encrypto is a third-party encryption tool available in the Mac App Store. It provides greater ease of use in encryption and decryption, based on a simple.
  2. How to Strongly Encrypt a File (for free) in OS X. Do NOT check the box to save the password in the Keychain else anyone who has access to your Mac can easily decrypt your DMG with a double-click.

You can use Disk Utility to create a disk image, which is a file that contains other files and folders.

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Note: You can burn information to a CD or DVD using the Burn command in the Finder. See Burn CDs and DVDs.

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.

  1. In the Disk Utility app on your Mac, choose File > New Image > Blank Image.

  2. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it. Best aio printers.

  3. In the Name field, enter the name for the disk image.

    This is the name that appears on your desktop and in the Finder sidebar, after you open the disk image.

  4. In the Size field, enter a size for the disk image.

  5. Click the Format pop-up menu, then choose the format for the disk:

    • If the disk image will be used with a Mac that has a solid state drive (SSD) and uses macOS 10.13 or later, choose APFS or APFS (Case-sensitive).

    • If the disk image will be used with a Mac with macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled).

    • If the disk image will be used with a Mac or Windows computer and is 32 GB or less, choose MS-DOS (FAT); if it’s over 32 GB, choose ExFAT.

  6. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  7. Click the Partitions pop-up menu, then choose a partition layout.

  8. Click the Image Format pop-up menu, then choose an option:

    • Sparse bundle disk image: Same as a sparse disk image (below), but the directory data for the image is stored differently. Uses the .sparsebundle file extension.

    • Sparse disk image: Creates an expandable file that shrinks and grows as needed. No additional space is used. Uses the .sparseimage file extension.

    • Read/write disk image: Allows you to add files to the disk image after it’s created. Uses the .dmg file extension.

    • DVD/CD master: Changes the size of the image to 177 MB (CD 8 cm). Uses the .cdr file extension.

  9. 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.

  10. In the Finder, copy your files to the mounted disk image, then eject it.

  11. Restore the disk image to a disk.

    For more information about disk image types, see the manual (man) page for hdiutil.

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.

  1. In the Disk Utility app on your Mac, select a disk, volume, or connected device in the sidebar.

  2. Choose File > New Image, then choose “Image from [device name].”

  3. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  4. Click the Format pop-up menu, then choose an option:

    • Read-only: The disk image can’t be written to, and is quicker to create and open.

    • Compressed: Compresses data, so the disk image is smaller than the original data. The disk image is read-only.

    • Read/write: Allows you to add files to the disk image after it’s created.

    • DVD/CD master: Can be used with third-party apps. It includes a copy of all sectors of the disk image, whether they’re used or not. When you use a master disk image to create other DVDs or CDs, all data is copied exactly.

  5. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  6. 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.

Important: Don’t create a disk image of a disk that you believe to be failing or that contains corrupted information. The disk image may not serve as a reliable backup.

For technical information about creating a restore disk image, see the Apple Software Restore (ASR) manual (man) page.

Create a disk image from a folder or connected device

You can create a disk image that contains the contents of a folder or connected device, such as a USB device. This method doesn’t copy a device’s free space to the disk image. For example, if a USB device or volume is 80 GB with 10 GB of data, the disk image will be 10 GB in size and include only data, not free space. You can then restore that disk image to another volume.

  1. In the Disk Utility app on your Mac, choose File > New Image, then choose Image from Folder.

  2. Select the folder or connected device in the dialog that appears, then click Open.

  3. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  4. To encrypt the disk image, click the Encryption pop-up menu, then choose an encryption option.

  5. Click the Image Format pop-up menu, then choose an option:

    • Read-only: The disk image can’t be written to, and is quicker to create and open.

    • Compressed: Compresses data, so the disk image is smaller than the original data. The disk image is read-only.

    • Read/write: Allows you to add files to the disk image after it’s created.

    • DVD/CD master: Can be used with third-party apps. It includes a copy of all sectors of the disk image, whether they’re used or not. When you use a master disk image to create other DVDs or CDs, all data is copied exactly.

    • Hybrid image (HFS+/ISO/UDF): This disk image is a combination of disk image formats and can be used with different file system standards, such as HFS, ISO, and UDF.

  6. 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.

For technical information about creating a restore disk image, see the Apple Software Restore (ASR) manual (man) page.

Create a secure disk image

If you have confidential documents that you don’t want others to see without your permission, you can put them in an encrypted disk image.

Note: If you want to protect the contents of the system disk, turn on FileVault using the FileVault pane of Security & Privacy Preferences.

  1. In the Disk Utility app on your Mac, choose File > New Image > Blank Image.

  2. Enter a filename for the disk image, add tags if necessary, then choose where to save it.

    This is the name that appears in the Finder, where you save the disk image file before opening it.

  3. In the Name field, enter the name for the disk image.

    This is the name that appears on your desktop and in the Finder sidebar, after you open the disk image.

  4. In the Size field, enter a size for the disk image.

  5. Click the Format pop-up menu, then choose a format:

    • If you’re using the encrypted disk image with a Mac computer using macOS 10.13 or later, choose APFS or APFS (Case-sensitive).

    • If you’re using the encrypted disk image with a Mac computer using macOS 10.12 or earlier, choose Mac OS Extended (Journaled) or Mac OS Extended (Case-sensitive, Journaled).

  6. Click the Encryption pop-up menu, then choose an encryption option.

  7. Enter and re-enter a password to unlock the disk image, then click Choose.

    WARNING: If you forget this password, you won’t be able to open the disk image and view any of the files.

  8. Use the default settings for the rest of the options:

    • Click the Partitions pop-up menu, then choose Single partition - GUID Partition Map.

    • Click the Image Format pop-up menu, then choose “read/write” disk image.

  9. 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.

  10. In the Finder , copy the documents you want to protect to the disk image.

  11. If you want to erase the original documents so they can’t be recovered, drag them to the Trash, then choose Finder > Empty Trash.

When you’re finished using the documents on the secure disk image, be sure to eject the disk image. As long as it’s available on your desktop, anyone with access to your computer can use the documents on it.

To access the data in a disk image, double-click it. It appears on your desktop, and you can add, remove, and edit files on it just as you would with a disk.

See alsoAdd a checksum to a disk image using Disk Utility on MacVerify that a disk image’s data isn’t corrupted using Disk Utility on MacRestore a disk image to a disk using Disk Utility on MacConvert a disk image to another format using Disk Utility on Mac

Dmg File Windows

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Disk Utility User Guide

When you format an internal or external storage device, you can encrypt and protect it with a password. If you encrypt an internal device, you must enter a password to access the device and its information. If you encrypt an external device, you must enter the password when you connect the device to your computer.

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Important: If you encrypt an external storage device, you can’t connect it to an AirPort base station for Time Machine backups.

To encrypt and protect the device with a password using Disk Utility, you must erase the device first. If the device contains files you want to save, be sure to copy them to another storage device or volume.

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  1. If the device contains any files you want to save, copy them to another storage device or volume.

  2. In the Disk Utility app on your Mac, choose View > Show All Devices.

  3. In the sidebar, select the storage device you want to encrypt.

  4. Click the Erase button in the toolbar.

  5. Enter a name for the volume.

  6. Click the Scheme pop-up menu, then choose GUID Partition Map.

  7. Click the Format pop-up menu, then choose an encrypted file system format.

  8. Enter and verify a password, then click Choose.

    To change the password later, select the volume in the sidebar, then choose File > Change Password.

  9. (Optional) If available, click Security Options, use the slider to choose how many times to write over the erased data, then click OK.

    Secure erase options are available only for some types of storage devices. If the Security Options button is not available, you can’t use Disk Utility to perform a secure erase on the storage device.

    Writing over the data three times meets the U.S. Department of Energy standard for securely erasing magnetic media. Writing over the data seven times meets the U.S. Department of Defense 5220-22-M standard.

  10. Click Erase, then click Done.

You can encrypt your data without erasing it by turning on FileVault in the Security & Privacy pane of System Preferences (see Encrypt Mac data with FileVault).

You can also encrypt a disk and protect it with a password without erasing it. See Encrypt disks or memory cards to protect your Mac information.

See alsoErase and reformat a storage device in Disk Utility on MacPartition a physical disk in Disk Utility on Mac
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