How to Partition a Drive in OS X El Capitan Using Disk Utility

This article explains how to partition a drive using Disk Utility on a Mac running OS X El Capitan. The process is similar in macOS Catalina, Mojave, High Sierra, and Sierra.

How to Partition a Drive in OS X El Capitan

Partitioning a drive with Disk Utility divides it into individual sections, each of which acts as a separate volume. It's possible to partition most types of storage devices, including SSDs, hard drives, and USB flash drives. Back up your data before creating new partitions on your device.

This example adds one partition to a hard drive. This same process can create any number of partitions.

1. From the Applications folder, launch Disk Utility. Or, type Disk Utility into Spotlight Search.

2. Select the drive you want to partition from the sidebar on the left. 

   Internal storage devices appear below the Internal section in the sidebar. External devices appear below the External section in the sidebar. You can only partition the drive, not any of the associated volumes.

3. The selected drive will appear in the right-hand pane with details about it, such as location, how it's connected, and the partition map in use.

4. Select the Partition button. You'll see a pie chart of how the drive is currently divided.

5. To add another volume, click the plus (+) button just below the pie chart.

6. Type a name for the volume in the Partition field.

7. Select the Format dropdown menu, then choose a file system format.

   OS X Extended (Journaled) is usually the default. It's the most commonly used file system on El Capitan Macs.

8. Enter the size or drag the resize control to increase or decrease the size of the volume.

9. Select Apply.

10. When you see Operation Successful, select Done.

11. You'll see your new partition listed in your Disk Utility sidebar.