How to partition an external hard drive mac​?

Partitioning an external hard drive is a vital task for users who want to organize their data effectively, create separate storage spaces, or format the drive for multiple operating systems. Whether you are a Mac user looking to organize your files, back up your data, or use your external drive for cross-platform purposes, partitioning can offer flexibility and better management of your storage.

What Is Partitioning?

Partitioning involves dividing a single physical hard drive into separate, logical sections. Each partition behaves like a separate hard drive, allowing you to organize and store different kinds of data on each one. These partitions can be formatted differently depending on your needs, making it possible to use the same external hard drive with multiple file systems.

For example, you could have one partition formatted as HFS+ (for macOS), another as exFAT (for cross-platform compatibility), and a third as NTFS (for Windows). Partitioning your drive helps to isolate data, prevents accidental file overwrites, and enhances performance in some use cases.

Why Partition an External Hard Drive on a Mac?

There are various reasons why you might want to partition an external hard drive:

Organization: Partitioning allows you to separate different kinds of files such as documents, photos, and backups, helping you stay organized.

Cross-Platform Compatibility: If you need to use the drive with both macOS and Windows, partitioning allows you to format one partition for macOS and another for Windows.

Backup: Create a dedicated partition for Time Machine backups or other important data.

Security: Isolate sensitive files from others on the same physical drive by placing them in a separate partition.

Performance: In some cases, multiple partitions can enhance the performance of certain applications by limiting the data stored in a single partition.

Prerequisites for Partitioning an External Hard Drive on a Mac

Before you proceed with partitioning your external hard drive, it’s important to meet the following prerequisites:

Backup Your Data: Partitioning a drive may involve erasing existing data. Ensure that you have backed up important files from your external drive before you begin.

External Hard Drive: You need an external hard drive connected to your Mac via USB, Thunderbolt, or other supported interfaces.

Disk Utility: You will use macOS’s Disk Utility to partition your external drive, which is located in the Applications > Utilities folder.

Step-by-Step Guide to Partitioning an External Hard Drive on Mac

Step 1: Open Disk Utility

Disk Utility is the macOS tool that allows users to manage disks and partitions. To open it, follow these steps:

Click on the Finder icon in your dock.

Select Applications from the sidebar.

Open the Utilities folder and double-click on Disk Utility to launch the application.

Step 2: Select the External Hard Drive

Once Disk Utility is open, you will see a list of all the storage devices connected to your Mac, including your internal drive and any external drives. To partition your external hard drive:

In the left sidebar, find the External section and select your external hard drive. Make sure to select the actual device (not the individual volume) to ensure that you’re partitioning the entire drive.

Step 3: Erase the External Drive (If Necessary)

If your external hard drive is not already formatted in a compatible file system, or if you wish to start fresh, you may need to erase it before partitioning. This step is optional, but it’s often necessary if you want to change the format or partition the drive.

After selecting your external hard drive, click the Erase button at the top of the Disk Utility window.

Choose a name for your external drive and select the file system format (such as APFS for macOS or exFAT for cross-platform use).

Click Erase to confirm. Note that this will delete all data on the drive, so ensure you’ve backed up any important files first.

Step 4: Partition the External Hard Drive

Once your external hard drive is prepared, follow these steps to partition it:

With the external drive selected, click the Partition button located at the top of the Disk Utility window.

You will be taken to the partition layout screen. Initially, you’ll see a single partition covering the entire drive.

To create additional partitions, click the + button below the pie chart. This will add a new partition.

Step 5: Adjust Partition Size

For each partition, you can adjust the size by dragging the divider between partitions or by manually entering the desired size in the “Size” field.

Partition Name: Click on the partition label to name it. This name will appear in Finder when the drive is connected to your Mac.

Format: Choose the file system format for each partition:

APFS: Use this for macOS-specific partitions.

HFS+: A legacy format for macOS, suitable for older versions of macOS.

exFAT: Ideal for drives that need to work with both macOS and Windows.

FAT32: Another cross-platform format, though it has a 4GB file size limit.

Size: Set the size for each partition. You can make them equal or set a custom size for each partition based on your needs.

Step 6: Apply the Partitioning Scheme

Once you have configured the partitions to your liking:

Click Apply to initiate the partitioning process.

Disk Utility will prompt you to confirm the partitioning. Since partitioning usually erases data, make sure you have a backup before proceeding.

Click Partition to begin the process. This can take a few minutes, depending on the size of the drive and the number of partitions.

Step 7: Wait for the Process to Complete

Disk Utility will show a progress bar while the partitioning process takes place. Once it’s done, you will see the partitions listed under the external hard drive in the Disk Utility window. Each partition will be represented as a separate volume, and you can start using them individually.

Step 8: Format Each Partition (If Needed)

After partitioning, each partition may need to be formatted before you can use it. If you chose a file system during the partition process, this step might be unnecessary. However, if you want to change the format of a partition, follow these steps:

Select the partition you wish to format from the list in Disk Utility.

Click the Erase button, choose the file system, and name the partition.

Click Erase to format the partition.

Step 9: Eject the External Drive

Once the partitioning and formatting are complete, you can safely eject the external hard drive:

In Disk Utility, select the external drive.

Click the Eject button next to the drive.

You can now disconnect your external hard drive from your Mac.

How to Verify Your Partitioning Scheme

To ensure that your external hard drive is partitioned correctly, you can check the partition layout in Disk Utility:

Reopen Disk Utility.

Select your external drive from the sidebar.

You should see the partitions listed under the external drive with their respective names, sizes, and formats.

You can also check in Finder to confirm that each partition appears as a separate volume.

Troubleshooting Partitioning Issues

Cannot Partition Drive: If you’re unable to partition your external drive, ensure that it’s correctly formatted. If the drive is already partitioned, you may need to erase it before proceeding.

File System Compatibility: Double-check that the file systems are compatible with your intended use. For example, exFAT is better for cross-platform usage than FAT32.

Disk Utility Crashes: If Disk Utility crashes during partitioning, try restarting your Mac and ensuring that no processes are interfering with Disk Utility. You may also want to try partitioning the drive using the Terminal.