How to Partition macOS Mojave Start-up Disk without Data Loss

Summary: Mac has an inbuilt storage drive with only one default partition i.e. the Macintosh HD. However, you at time need to divide the internal drive into a logical partition for specific task. Even external drive needs partitioning. In this blog, we will talk about the tried and tested method to partition macOS Mojave’s start-up disk as well as an external drive without the fear of losing data.

How to Partition macOS Mojave Start-up Disk without Data Loss

The systematic steps to partition macOS Mojave start-up disk is as follows:

  1. Restart Mac and immediately press & hold the Command and R keys simultaneously.
  2. Once in the recovery mode, from the macOS Utilities dialog box select Disk Utility.
    macOS Utilities
  3. If only volumes are visible in the sidebar of the Disk Utility window, then go to View > Show All Devices.
    Show all devices
  4. From the sidebar, select the start-up drive and click the Partition icon present on the top pane of the Disk Utility window.
  5. From the Apple File System Space Sharing message box, click the Partition
    Partition macOS Mojave
  6. Add the plus (+) button to add a partition or specify the size and unit from the right. Fill other partition information, such as Name and Format then click Apply.
    partition Mojave
  7. Disk Utility processing the request.
  8. Once the macOS Mojave has applied the changes to the startup disk, click Done. (Untitled partition created successfully)

Note: You can use the same steps to partition any volume other than the startup disk. Further, you can implement the same steps on macOS High Sierra with APFS or HFS partitioned start-up disk.

The systematic steps to partition an external storage drive is as follows:

Please note, you don’t need to boot into recovery mode to partition an external hard drive.

  1. Connect the external storage drive to your Mac.
  2. Open Disk Utility from Spotlight.
  3. From the sidebar, select the external storage drive.
  4. Click Partition from the top pane.
  5. Fill in the partition Name and Format.
  6. Specify the size and unit or use the plus (+) icon and resize the partition map.

Recommendation: Backup your data before you partition any drive be it internal or external. Backup helps you to be prepared in case partitioning goes wrong, and you can use the backup to restore accidentally lost data.


The blog has highlighted the correct method to partition macOS Mojave start-up drive without losing any data. In case you have not backed up the storage drive before performing the drive partitioning, then chances of data loss due to improper partitioning or other untoward reasons is high. Do not worry; if you have lost your data due to partitioning, you ought to scan the affected drive using one of the best Mac data recovery software. For any queries related to macOS Big Sur, Catalina, and Mojave partitioning, write your comments below.

  1. Nina Barett February 28, 2019
    • Vishal February 28, 2019
  2. Latoya Newman December 27, 2018
    • Vishal December 28, 2018

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