How to Format a USB Drive on a Mac

Authored by: Tech Pro Team

1. Introduction

USB drives are great for carrying or backing up data. Formatting is the process that erases all existing data on a USB drive and sets up the file system it will use. The file system is what tells the drive how to store the data that is to be written to, read or deleted from it. The type of file system that is needed on a USB drive varies depending on the type of device it will be used with.

While most devices will alert you if you connect a USB drive with an incompatible file system that needs to be formatted, refer to your device's documentation to find out what file systems are compatible with your device.

This guide will show you how to format a USB drive using a Windows PC.

What You'll Need:

  • No extra tools or supplies are needed.


Before You Begin:

Extra instructions.

  • hyperlink


macOS Logo.

Types of USB Drives

While the process to format USB drives is the same, they may come in different physical forms:

  • USB flash drives
USB Thumbdrives.
  • External USB hard drives or solid state drives
USB external drive.


2. Format a USB Drive with a Mac

Any and all data on the USB drive will be destroyed during this process. Make sure the drive is blank, or copy the data to a safe place before proceeding.

  1. Insert a USB disk into your USB port.
  2. macOS will recognize the disk and show its icon on the desktop.
macOS desktop showing USB Disk connected.
  1. Launch Disk Utility.
  2. Select Search in the top-right corner.
Spotlight icon highlighted.
  1. type in "Disk Utility". Select the Disk Utility search result.
Disk Utility search in Spotlight.
  1. Select your USB Disk from the list on the left.
Disk Utility with USB Disk highlighted.
  1. Select Erase at the top.
Disk Utility with Erase highlighted.
  1. Type in a Name for the drive, then select a Format.
Erase dialog with Name and Format highlighted.
  1. Format types to select from are shown below.
macOS drive format types.
  1. Select Erase.
  1. A progress bar will open. Wait will the disk is formatted.
  1. Once complete, select Done.
  1. Quit Disk Utility. Select the Disk Utility menu at the top, then Quit Disk Utility.
Disk Utility menu with Quit Disk Utility highlighted.

If you cannot find success with the above guide, please refer to the additional steps below:

Formatting a USB or external hard drive for a Mac computer is a common task that can be crucial for various reasons. This blog post will delve into the reasons for formatting these devices for Mac and provide a step-by-step guide on how to do it.

Why Format a USB or External Hard Drive for Mac?

Compatibility: The most common reason to format a USB or external hard drive for a Mac is to ensure compatibility with macOS. Mac computers use a different file system compared to Windows, and formatting the drive ensures it can be read and written on a Mac without issues.


Performance Improvement: Formatting can also improve the performance of your device. Over time, drives can become cluttered with unnecessary data, leading to slower performance.


Data Security: When you're giving away or selling your external drive, formatting is essential to prevent the next user from accessing your personal data.


Error Fixing: If your drive has errors or has become corrupt, formatting can often be a simple solution to fix these issues.


Switching File Systems: You might need to switch between file systems (like from FAT32 to exFAT or HFS+) to meet specific requirements, such as file size limits or compatibility with other operating systems.


How to Format a USB or External Hard Drive for Mac


Before You Begin


Backup Data: Ensure you have backed up any important data from the USB or external hard drive, as formatting will erase all data on the drive.

Power Supply: If you're formatting an external hard drive, ensure it's connected to a power source if required.


Step-by-Step Guide

Connect the Drive: Plug your USB or external hard drive into your Mac.

Open Disk Utility: You can find Disk Utility by searching in Spotlight or navigating through Finder > Applications > Utilities.

Select the Drive: In Disk Utility, you'll see a list of drives. Select the USB or external hard drive you want to format.

Choose ‘Erase’: Click on the ‘Erase’ button at the top of the Disk Utility window.


Set Format and Scheme:

Format: Choose a file system format.

For Mac-only use, select ‘Mac OS Extended (Journaled)’.

For cross-platform use, select ‘exFAT’ (for larger file sizes) or ‘FAT32’ (for smaller file sizes but with a 4GB file size limit).

Scheme: Select ‘GUID Partition Map’ for newer Macs or ‘Master Boot Record’ for older ones.


Name Your Drive: Enter a name for your formatted drive.

Erase and Format: Click ‘Erase’ to begin the formatting process. This may take a few minutes depending on the size and type of the drive.

Eject the Drive: Once the process is complete, eject the drive properly by right-clicking on its icon on the desktop and selecting ‘Eject’.


After Formatting


Time Machine Backup: If you're planning to use the drive for Time Machine backups, you can set it up in System Preferences > Time Machine.

Data Transfer: Transfer any data back onto the drive if needed.



Formatting a USB or external hard drive for your Mac ensures compatibility, optimizes performance, and helps in data management. By following the steps outlined above, you can easily format your drive for optimal use with your Mac computer. Always remember to backup important data before proceeding with formatting to avoid any data loss.