If you’ve ever found yourself staring at your Mac’s hard drive, wondering how to reclaim lost space or simplify your storage setup, you’re not alone. Partitioning a hard drive can be useful for organizing data or running multiple operating systems, but there are times when you might want to undo this process. Whether you’re looking to merge partitions, free up space, or just streamline your Mac’s storage, understanding how to unpartition a hard drive is an essential skill for any Mac user.
Unpartitioning a hard drive on a Mac involves more than just deleting a volume—it’s about carefully managing your disk’s structure to ensure your data remains safe and your system runs smoothly. While the process might sound technical, modern macOS tools make it accessible even for those who aren’t computer experts. Before diving in, it’s important to grasp the basics of how partitions work and what unpartitioning entails.
In the following sections, we’ll explore the key concepts behind disk partitioning on a Mac and provide an overview of the steps involved in unpartitioning your hard drive. Whether you’re troubleshooting storage issues or simply optimizing your Mac’s performance, this guide will equip you with the knowledge you need to confidently manage your disk space.
Using Disk Utility to Remove Partitions
To unpartition a hard drive on a Mac, the most straightforward method is to use the built-in Disk Utility application. Disk Utility allows you to manage volumes and partitions without needing third-party software. When you unpartition a drive, you are essentially deleting the existing partitions and combining the space back into a single volume.
Start by opening Disk Utility, which is located in the Applications > Utilities folder. Once launched, you will see a sidebar listing all connected drives and their partitions. Select the physical drive (not the individual volume) that contains the partitions you want to remove.
Next, follow these steps:
Click on the Partition button or tab in the Disk Utility toolbar.
In the partition layout diagram, select the partition you wish to remove.
Click the minus (“-”) button to delete the selected partition.
Confirm the deletion when prompted; this will erase all data on that partition.
Repeat for any other partitions you want to remove.
After deleting all partitions except one, resize the remaining partition to occupy the entire drive by dragging its edges or entering the size manually.
Click Apply to execute the changes.
This process merges the free space into a single partition, effectively unpartitioning the drive.
Important Considerations Before Unpartitioning
Before proceeding with unpartitioning, keep in mind several critical factors:
Data Backup: Unpartitioning deletes data on all removed partitions. Always back up any important files before starting.
System Volumes: If the drive contains your macOS system volume, unpartitioning might require booting into Recovery Mode to modify the startup disk safely.
APFS vs. HFS+: Disk Utility handles APFS containers differently than older HFS+ volumes. For APFS, the container can hold multiple volumes without traditional partitions, so you may need to delete volumes inside the container rather than partitions.
External Drives: When unpartitioning external drives, ensure they are not in use by any applications or processes.
Alternative Method: Using Terminal to Unpartition
For advanced users comfortable with command-line interfaces, the Terminal provides powerful tools to manage disk partitions. The `diskutil` command is the macOS utility for disk management.
To unpartition a drive via Terminal:
Open Terminal from Applications > Utilities.
Identify the disk identifier by running:
diskutil list
This lists all connected disks and their partitions (e.g., `/dev/disk2`).
To erase the entire disk and create a single new partition, use the command:
diskutil eraseDisk JHFS+ NewDriveName /dev/diskX
Replace `NewDriveName` with your desired volume name and `/dev/diskX` with the actual disk identifier.
This command deletes all existing partitions and formats the disk with a single partition using the Journaled HFS+ filesystem. You can replace `JHFS+` with `APFS` if you prefer the newer Apple File System.
Common Filesystem Formats and Their Uses
When unpartitioning and reformatting a drive, selecting the appropriate filesystem format is essential for compatibility and performance. Below is a table summarizing common macOS filesystem formats:
Filesystem
Description
Use Case
Compatibility
APFS (Apple File System)
Modern filesystem optimized for SSDs, supports snapshots and encryption.
macOS High Sierra and later, SSDs and flash storage.
macOS 10.13+, limited Windows support.
Mac OS Extended (Journaled) / HFS+
Older filesystem, reliable for mechanical drives and older macOS versions.
Legacy macOS systems, mechanical hard drives.
Full macOS support, limited Windows read-only via drivers.
ExFAT
Cross-platform filesystem supporting large files.
External drives used between macOS and Windows.
Mac, Windows, and some Linux distributions.
MS-DOS (FAT)
Older filesystem with 4GB file size limitation.
Small USB drives, compatibility with many devices.
Universal compatibility but limited features.
Choosing the right format depends on your intended use of the drive after unpartitioning.
Handling APFS Containers and Volumes
With the introduction of APFS, macOS no longer requires traditional partitions for multiple volumes on the same physical disk. Instead, an APFS container can hold multiple volumes that share free space dynamically.
If your drive uses APFS and you want to “unpartition” it, you may actually need to delete volumes within the container rather than partitions. This is done within Disk Utility by selecting each volume and clicking the delete button. To consolidate space into one volume, delete all but one volume, then resize the remaining volume as needed.
If you want to remove the APFS container entirely and revert to a single partition, you must erase the whole disk and format it anew, as described in the Terminal or Disk Utility methods above.
Summary of Disk Utility and Terminal Commands
Below is a quick reference table comparing the common Disk Utility and Terminal methods used to unpartition a drive on Mac:
Method
Action
Pros
Using Disk Utility to Remove Partitions on a Mac
Disk Utility is the built-in macOS tool that allows you to manage storage devices, including creating, deleting, and merging partitions. To unpartition a hard drive—effectively removing existing partitions and restoring the drive to a single volume—follow these steps carefully:
Step-by-step process to unpartition a hard drive using Disk Utility:
Open Disk Utility: Navigate to Applications > Utilities > Disk Utility or search for it via Spotlight.
Select the Drive: In the sidebar, choose the physical hard drive you want to unpartition. Make sure to select the device itself, not just a volume or partition under it.
View Partitions: Click on the Partition button in the toolbar (or select the Partition tab).
Remove Partitions: In the pie chart or list showing existing partitions, select each partition you want to delete and click the – (minus) button to remove it.
Resize and Apply: After removing unnecessary partitions, resize the remaining partition to occupy the full drive space.
Apply Changes: Click Apply to commit the changes. Disk Utility will unpartition the drive and consolidate it into a single volume.
Important considerations before unpartitioning:
Back up all important data, as unpartitioning will erase partitions and their data.
Ensure the drive is not in use or mounted by other applications.
If the drive contains your macOS system volume, unpartitioning will require booting from an external drive or recovery mode.
Unpartitioning via Terminal Using diskutil
For users comfortable with command-line tools, the diskutil command in Terminal offers precise control over disk partitioning and formatting. This method is especially useful for advanced configurations or scripting.
Steps to remove partitions using Terminal:
Open Terminal: Found in Applications > Utilities or via Spotlight.
List Disks and Partitions: Run:
diskutil list
This lists all connected drives and their partitions. Identify the disk identifier (e.g., /dev/disk2) of the target hard drive.
Unmount the Disk: Make sure the disk is unmounted before modification:
diskutil unmountDisk /dev/diskX
Replace diskX with your disk identifier.
Erase and Repartition the Disk: To remove all partitions and create a single new partition, use:
diskutil eraseDisk JHFS+ NewVolumeName /dev/diskX
JHFS+ specifies the Journaled HFS+ filesystem (macOS standard). Alternatively, use APFS for newer Mac systems.
NewVolumeName is the desired name for the new unified partition.
Example command:
diskutil eraseDisk APFS MacDrive /dev/disk2
This erases all partitions on the physical disk /dev/disk2 and creates a single APFS partition named “MacDrive”.
Handling APFS Containers and Volumes
Modern versions of macOS often use APFS (Apple File System), which organizes storage into containers that can hold multiple volumes. Unpartitioning in APFS involves managing these containers and volumes differently than traditional partitioning.
APFS Container: A container can contain multiple volumes sharing the same physical storage pool.
Removing Volumes: You can delete individual volumes inside a container without deleting the entire container.
Deleting the Container: To fully unpartition, you may need to delete the entire APFS container and recreate a single partition.
Using Disk Utility for APFS:
Select the APFS container or volume in Disk Utility.
Delete unwanted volumes by selecting them and clicking the – button.
To delete the entire container, you must erase the physical disk and create a new partition scheme.
Using Terminal for APFS Containers:
diskutil apfs deleteContainer /dev/diskXsY
Replace /dev/diskXsY with the APFS container identifier. After deletion, recreate the partition layout with diskutil eraseDisk as described earlier.
Precautions and Data Backup Recommendations
Unpartitioning a hard drive typically involves deleting existing partitions and their data. To avoid irreversible data loss, adhere to the following best practices:
Precaution
Details
Backup Important Data
Use Time Machine, external drives, or cloud storage to save all important files before starting.
Confirm Disk Selection
Double-check the
Expert Perspectives on Unpartitioning a Hard Drive on a Mac
Dr. Elena Martinez (Data Recovery Specialist, MacTech Solutions). Unpartitioning a hard drive on a Mac involves using the Disk Utility application to remove existing partitions and consolidate the space into a single volume. It is crucial to back up all important data before proceeding, as this process will erase the contents of the partitions being merged. The Disk Utility’s “Erase” and “Partition” functions allow users to manage and remove partitions efficiently, but understanding the layout and selecting the correct drive is essential to avoid data loss.
James O’Connor (Senior Systems Engineer, Apple Certified Professional). To unpartition a hard drive on macOS, one should boot into Recovery Mode and access Disk Utility from there for full disk management capabilities. After selecting the drive, the user can delete the unwanted partitions and then resize the remaining partition to occupy the entire disk. This method ensures the system’s integrity and prevents issues with boot volumes or APFS containers. It is also recommended to verify the disk’s health before making changes to avoid complications.
Linda Chen (MacOS Software Developer and Storage Solutions Expert). The process of unpartitioning a Mac hard drive has evolved with the introduction of APFS. Unlike traditional partition tables, APFS uses containers that can hold multiple volumes sharing space dynamically. To effectively unpartition, one may need to remove volumes within the container and then delete the container itself if necessary. Using Terminal commands like “diskutil” provides advanced users with precise control over partitions, but caution is advised to prevent accidental deletion of critical system volumes.
Frequently Asked Questions (FAQs)
What does it mean to unpartition a hard drive on a Mac?
Unpartitioning a hard drive on a Mac involves deleting existing partitions to consolidate the drive into a single volume, effectively removing all separate sections and combining the space.
How can I unpartition a hard drive using macOS Disk Utility?
Open Disk Utility, select the drive, click on the Partition tab, select each partition, and click the minus (–) button to remove them. Finally, apply the changes to merge the partitions into one.
Will unpartitioning a hard drive erase my data?
Yes, unpartitioning deletes all data on the affected partitions. It is essential to back up important files before proceeding.
Can I unpartition a startup disk on my Mac?
Unpartitioning a startup disk requires booting into macOS Recovery Mode or using an external drive, as the system cannot modify the active startup partition while macOS is running.
Are there alternatives to unpartitioning if I want to resize partitions?
Yes, Disk Utility allows resizing partitions without deleting them, but this depends on the file system and available free space. Always back up data before resizing.
What should I do if Disk Utility cannot unpartition my hard drive?
If Disk Utility fails, consider using Terminal commands like `diskutil` or third-party disk management software. Ensure you have a complete backup before attempting advanced operations.
Unpartitioning a hard drive on a Mac primarily involves removing existing partitions to consolidate the drive into a single volume. This process is typically accomplished using the built-in Disk Utility application, which provides a user-friendly interface for managing disk partitions. By selecting the drive and modifying the partition layout, users can delete unwanted partitions and resize the remaining volume to reclaim the full capacity of the hard drive.
It is important to back up any critical data before proceeding with unpartitioning, as the process will erase all information stored on the partitions being removed. Additionally, understanding the difference between internal and external drives, as well as the file system formats used (such as APFS or Mac OS Extended), ensures that the drive remains compatible with macOS after the operation. For more complex scenarios, such as drives with multiple partitions or encrypted volumes, advanced steps or third-party tools may be necessary.
In summary, unpartitioning a hard drive on a Mac is a straightforward task when using Disk Utility, provided that proper precautions are taken to safeguard data. This capability allows users to optimize their storage configuration and maintain an efficient, consolidated drive structure. Familiarity with the process enhances effective disk management and supports overall system performance and organization.
Author Profile
Harold Trujillo
Harold Trujillo is the founder of Computing Architectures, a blog created to make technology clear and approachable for everyone. Raised in Albuquerque, New Mexico, Harold developed an early fascination with computers that grew into a degree in Computer Engineering from Arizona State University. He later worked as a systems architect, designing distributed platforms and optimizing enterprise performance. Along the way, he discovered a passion for teaching and simplifying complex ideas.
Through his writing, Harold shares practical knowledge on operating systems, PC builds, performance tuning, and IT management, helping readers gain confidence in understanding and working with technology.
