disk image using Disk Utility

Create a disk image

Use Disk Utility to create disk images. 

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

Create a blank disk image for storage

Create an empty disk image, fill it with data, then use it to create disks, CDs, or DVDs.

  1. Choose File > New Image > Blank Image.

  2. Enter a file name 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 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 Sierra 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 image, 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

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. Select a disk, volume, or connected device in the sidebar.

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

  3. Enter a file name 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

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. 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 file name 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. Choose File > New Image > Blank Image.

  2. Enter a file name 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 High Sierra, choose APFS (Journaled) or APFS (Case-sensitive, Journaled). 

    • If you’re using the encrypted disk image with a Mac computer using macOS Sierra 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 account 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.



iOS multitasking

Use Multitasking on your iPad

On your iPad with iOS 11 or later, you can use Multitasking to work with two apps at the same time, answer emails while watching a video, switch apps using gestures, and more.

Switch apps using gestures

Use Multitasking gestures on your iPad to quickly see the app switcher, switch to another app, or return to the Home screen:

  • See the app switcher: In iOS 12, swipe up with one finger from the bottom edge of the screen and hold in the middle of the screen until the app switcher appears. You can also double-click the Home button to see all of your open apps. Swipe right with one finger to find and open a different app.
  • Switch apps: While using an app, swipe left or right with four or five fingers to switch to a previously used app.
  • Return to the Home screen: In iOS 12, while using an app, swipe up from the bottom edge of the screen. You can also pinch four or five fingers together on the screen to return to the Home screen.

Use the Dock to work with more apps simultaneously

The Dock lets you instantly open and switch apps from any app you're in. You can even customize the left side of the Dock with your favorite apps. And on the right side, you can see apps that you recently used and apps that are open on your iPhone and Mac.

You can find the Dock at the bottom of the Home screen. To see the Dock while you're using an app, slide one finger up from the bottom edge of the screen until the Dock appears, then release.

To customize the Dock with your favorite apps, touch and hold an app on the Home screen, then immediately drag it to the left side of the Dock.

To remove an app from the Dock, touch and hold an app on the left side of the Dock, then immediately drag it off.

Use two apps at the same time

The Dock makes it easy to work with multiple apps at the same time. Drag an app out of the Dock to make a Slide Over or drag it to the right or left edge of the screen to make a Split View. You can even work on one app in Slide Over, view two apps in Split View, and watch a movie or use FaceTime in Picture in Picture — all on the same screen.

Open a second app with Slide Over

Use Slide Over to work on an app that slides in front of any open app, even over two open apps in Split View:

  1. Open an app.
  2. Swipe up from the bottom of the screen to open the Dock.
  3. On the Dock, touch and hold the second app that you want to open, then drag it to the screen.

If you're working with two apps in Split View and want to open a third app in Slide Over, just swipe up from the bottom of the screen to open the Dock. Then drag the app on top of the app divider.

To move the app that's open in Slide Over, touch and hold , then drag it to the left or right side of the screen.

You can also move the app that's open in Slide Over off the screen and slide it back when you want to use it. Just place your finger on  and drag the app to the right and off the screen. When you want to use the app again, swipe left from the right side of the screen.

You can use Slide Over with iPad Pro, iPad (5th generation and later), iPad Air and later, or iPad mini 2 and later.

Use two apps at the same time with Split View

With Split View, you can use two apps at the same time. For example, you can view photos while you compose an email. Or look at a location in Maps while you search for vacation ideas in Safari.

How to use Split View:

  1. Open an app.
  2. Swipe up from the bottom of the screen to open the Dock.
  3. On the Dock, touch and hold the second app that you want to open, then drag it off the dock.
  4. When the app opens in Slide Over, drag  down.

How to adjust Split View:

  • To give the apps equal space on the screen, drag the app divider to the center of the screen.
  • To turn a Split View into a Slide Over, swipe down from the top of the app.
  • To close Split View, drag the app divider over the app that you want to close.

Learn how to use Split View in Safari to see two websites at the same time on your iPad.

You can use Split View with iPad Pro, iPad (5th generation and later), iPad Air 2, or iPad mini 4.

Use apps while you watch a video with Picture in Picture

With Picture in Picture, you can do things like respond to an email while watching a TV show. If you’re using FaceTime or watching a movie, tap  and the video screen scales down to a corner of your display. Then you can open a second app and the video will continue to play.

To move the video, drag it to another corner. To return the video to full screen, tap  on the left corner of the video. You can also hide the video by dragging it to the left or right edge of your display. Tap the arrow icon to make the video reappear.

You can use Picture in Picture with iPad Pro, iPad (5th generation and later), iPad Air and later, or iPad mini 2 and later.

Drag and drop between apps

With drag and drop, you can move text, photos, and files from one app to another. For example, you can drag text from Safari into a note, an image from Photos into a an email or a calendar event into a text message:

  1. Open the two apps in Split View or Slide Over.
  2. Touch and hold the item until it lifts up. To select multiple items, touch and hold an item, drag it slightly, then continue to hold it while you tap additional items with another finger. A badge indicates the number of selected items. To drag and drop text, select the text first, then touch and hold the text until it lifts up.
  3. Drag the item to the other app and drop it.

Turn Multitasking features on or off

To turn Multitasking features on or off, go to Settings > General > Multitasking & Dock, then you can do the following:

  • Allow Multiple Apps: Turn off if you don't want to use Slide Over or Split View.
  • Persistent Video Overlay: Turn off if you don't want to use Picture in Picture.
  • Gestures: Turn off if you don't want to use Multitasking gestures to see the app switcher, return to the Home screen, and more.
  • Show Suggested and Recent Apps: Turn on to see recently used apps on the right side of the Dock.

Use Background App Refresh

After you switch to a different app, some apps run for a short period of time before they're set to a suspended state. Apps that are in a suspended state aren’t actively in use, open, or taking up system resources. With Background App Refresh, suspended apps can check for updates and new content.

If you want suspended apps to check for new content, go to Settings > General > Background App Refresh and turn on Background App Refresh. If you quit an app from the app switcher, it might not be able to run or check for new content before you open it again.