Disk Utility for macOS Sierra: Create partitions on a physical disk with Disk Utility

When dividing a storage device, individual partitions are created, which appear as separate volumes in the Devices section of the Finder sidebar. You may need to split a disk into partitions if you want to install multiple operating systems or if you need to change the format of the device.

If you are going to partition an internal physical disk into partitions to install Windows, use the Boot Camp Assistant.

WARNING: To prevent loss of data on your Fusion Drive, do not connect it to a Mac that uses an OS X version earlier than 10.8.5. For more information, see the Apple Support article Connect Fusion Drive from OS X Mavericks only to OS X Mountain Lion v10.8.5 or later .

You can easily create new partitions on a device with at least one volume containing data, if space is available.

Important: As a precaution, it is best to back up the data before creating new partitions on the device.

Add a volume to a device without deleting existing data

  1. Select the device in the sidebar and click the Partition button .The internal storage devices are shown in the Internal section of the sidebar. External storage devices are displayed in the External section of the sidebar.When you select a volume that already has data, the pie chart shows a shaded area that represents the amount of data present in the volume and another unshaded area that represents the amount of available free space for another volume. Disk Utility also indicates whether the volume can be deleted or resized.If you see a small volume with an asterisk, the partition will be smaller than it can be represented on a correct scale on the graph.
  2. Click the Add button .Disk Utility divides the volume into two, leaves the data on one volume and creates a new empty volume. If the existing volume has an occupancy of less than 50%, Disk Utility creates two volumes of the same size. Otherwise, it creates a volume of the size that occupy the existing data and another one with the remaining space. Depending on the space available, you can create multiple volumes by selecting the new volume and clicking the Add button.
  3. Click on the volumes in the chart on the left and enter a name for each.For MS-DOS (FAT) and ExFAT volumes, the name can only be up to eleven characters.
  4. Specify the size or drag the slider to increase or decrease the size of each volume.
  5. For each volume, click the Format drop-down menu and select a format.
    • Mac OS Plus (with registration): uses the Mac format (HFS Plus with registration) to protect the integrity of the hierarchical file system.
    • Mac OS Plus (with registration, encrypted): uses the Mac format, requires password and encrypts the partition.
    • Mac OS Plus (upper case / minus., With registration): uses the Mac format and distinguishes the uppercase and lowercase letters from the names of folders and files. For example, the “Tasks” and “TASKS” folders are different.
    • Mac OS Plus (registry key, encrypted): uses the Mac format, distinguishes the case of folder names, requires password, and encrypts the volume.
    • MS-DOS (FAT): Used for Windows volumes up to 32 GB.
    • ExFAT: Used for Windows volumes of more than 32 GB.
  6. Click Apply.Click “Show details” to see the detailed process of creating a new volume.
  7. When Disk Utility has finished creating the volumes, click OK.

After dividing a storage device into partitions, an icon for each volume is displayed in the Disk Utility sidebar and the Finder sidebar.

Enlarge a volume

If you have multiple volumes on a device and one of them is running out of space, you can extend it without losing any of the files it contains.

To enlarge a volume, you must delete the next volume on the device, and then move the endpoint of the volume you want to expand to the freed space. The last volume of a device can not be extended.

WARNING: Deleting a volume will erase all your data. Do not forget to back up the data before you start.

  1. In the sidebar, select the device that contains the volume you want to magnify, and then click the Partition button.
  2. In the chart on the left, select the volume you want to delete, and then click the Delete button.
  3. Click Apply.The volume will be deleted and reformatted, and all free space will be allocated to the previous volume.
  4. Click OK.

Delete and re-partition a device

You can erase all volumes on a device and create new volumes. For example, if you want to change the partition map of a USB, Thunderbolt or other storage device from the boot master record (MBR) or partition map GUID. If you only want to delete a volume, see Delete a volume .

WARNING: Deleting and partitioning a device will destroy all data in the device volumes.

  1. In the sidebar, select the device you want to delete and repartition to partitions, and then click Delete.

    Note: The device containing its boot volume can not be erased.

  2. Enter a name for the initial volume.
  3. Click the Map drop-down menu and select a format for the initial partition.For MS-DOS and ExFAT partitions, the name can only be 11 characters or less.
    • Partition Map GUID: Used with all Mac computers with Intel processor.
    • Master Boot Record (MBR): Used with Windows partitions to be formatted as MS-DOS (FAT) or ExFAT.
    • Apple Partition Map: Used to support compatibility with Macs with an older PowerPC processor.
  4. Click Delete, and then click OK.

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