How to Reinstall macOS from USB Drive on a Mac

Apple’s macOS, previously known as Mac OS X and OS X, is a powerful, stable, and user-friendly operating system designed specifically for Mac computers. Since its initial release in 2001, macOS has undergone significant improvements and updates, with newer versions boasting enhanced performance, security, and features.

This article aims to provide a comprehensive guide for reinstalling macOS on your Mac from a USB drive. We will walk you through the process, including why and when you might need to reinstall macOS, the benefits of using a bootable USB drive, and the necessary steps to prepare, create, and install macOS using a USB drive.

Why You Need to Reinstall macOS on a Mac

If your Mac is experiencing persistent issues like crashing, freezing, or unresponsiveness, reinstalling macOS might be the most effective solution. In addition, a fresh macOS installation can help eliminate clutter accumulated over time, such as outdated software, cache files, and unnecessary data.

It is also important to note that reinstalling macOS ensures you have the latest security patches and updates, protecting your system from potential threats.

Lastly,  a clean installation of macOS ensures personal data removal and prepares the device for the new user.

Bootable USB Advantages Over Direct Upgrade

Using a bootable USB drive to reinstall macOS offers several advantages compared to performing a direct upgrade:

Recovery: A bootable USB drive serves as a reliable recovery solution in case of system failure or corruption, allowing you to reinstall macOS without needing an internet connection.

Compatibility: A bootable USB drive can be used to install macOS on multiple Macs without the need for individual downloads or installations.

Control: A bootable USB drive allows for a clean installation, giving you the option to erase your hard drive and start fresh, whereas a direct upgrade might retain old files and configurations.

What You Should Prepare Before Reinstalling macOS

Before reinstalling macOS, ensure the following:

Backup your data: Use Time Machine or other backup solutions to save important files, as reinstalling macOS may erase your data.

Check for compatibility: Verify that your Mac supports the macOS version you plan to install.

A bootable macOS USB drive: Obtain a USB drive with at least 16GB of storage and create a bootable macOS USB.

Internet connection: Ensure you have a stable internet connection to download the macOS installation file.

Choose the Best macOS Version for Your Mac

Selecting the best macOS version for your Mac is crucial for optimizing performance, ensuring compatibility, and enjoying the latest features. There are several factors to consider, including hardware requirements, software compatibility, and personal preferences. This guide will help you make an informed decision when choosing the best macOS version for your Mac.

Check Your Mac’s Compatibility

The first step in choosing the best macOS version is determining which versions are compatible with your Mac. To do this,  click on the Apple icon in the top-left corner of your screen and select "About This Mac." Note your Mac’s model and year, which will be displayed in the Overview tab.

Visit Apple’s macOS support page ( and check the compatibility section for each macOS version. Identify which versions are compatible with your Mac model and year.

Evaluate Hardware Requirements

Each macOS version has specific hardware requirements, such as minimum RAM, available storage, and processor capabilities. Compare your Mac’s hardware specifications to the requirements for each compatible macOS version. Choose a version that your Mac can comfortably run, ensuring optimal performance.

Consider Software Compatibility

Software compatibility is another essential factor to consider when selecting a macOS version. Some applications may not be compatible with newer macOS versions or may require updates to function correctly. Before upgrading or downgrading, verify that your frequently used applications will continue to work with the new macOS version. Check for updates, patches, or alternative software, if necessary.

Weigh Stability and Security

Stability and security are essential aspects of an operating system. Generally, newer macOS versions offer improved stability and security features. However, some users may prefer to stick with a slightly older version if it has proven to be stable and reliable. When making your decision, weigh the importance of stability, security, and the new features offered by each macOS version.
Personal Preferences and Needs

Your personal preferences and needs should also be considered when choosing the best macOS version for your Mac. Think about how you use your Mac daily and the features that would best suit your workflow. If you prefer a specific user interface, certain features, or have special requirements, take these factors into account when making your decision.

How to Create a Bootable macOS USB with DMG Editor

Creating a bootable macOS USB drive allows you to reinstall macOS on your Mac or upgrade to a new version. DMG Editor is a third-party tool that simplifies this process by streamlining the creation of a bootable USB drive. In this guide, we will walk you through the steps to create a bootable macOS USB drive using DMG Editor.

Step 1: Before creating a bootable USB drive, you’ll need the macOS installation file (.dmg), which can be downloaded from The installation file will typically be in the DMG format.

Step 2: Prepare a USB drive with at least 16GB of storage capacity. The USB drive will be formatted during the process, so ensure you’ve backed up any important data.

Step 3: Download DMG Editor from the official website or an approved source. Follow the installation instructions provided on the website to install the software on your Mac.

Step 4: Launch DMG Editor on your Mac.In the main menu, select "Burn" or a similar option, depending on the version of DMG Editor you are using.

Step 5: Locate and select the macOS installation file (DMG) you downloaded earlier. Choose the formatted USB drive as the destination for the bootable USB drive.

Step 6: Finally, click "Burn" to initiate the process. DMG Editor will format the USB drive and copy the necessary files to make it bootable. This process may take some time, so be patient.

Once DMG Editor has successfully created the bootable USB drive, a confirmation message will appear.

Video: How to Create a macOS  Bootable USB on MAC

Boot Your Mac from USB Drive and Start Installing macOS

Booting your Mac from a USB drive is useful when you need to install or reinstall macOS, run diagnostics, or access recovery tools. This guide will walk you through the process of booting your Mac from a USB drive.

Step 1. Prepare a Bootable USB Drive

Before booting your Mac from a USB drive, ensure you have a bootable USB drive prepared. The USB drive should contain a macOS installer, a recovery tool, or a diagnostic utility, depending on your needs. If you don’t have a bootable USB drive yet, follow a guide to create one using a tool like DMG Editor or Terminal.

Step 2. Insert the USB Drive into Your Mac

Insert the bootable USB drive into an available USB port on your Mac. If you’re using a newer Mac with USB-C or Thunderbolt ports, you may need a USB-A to USB-C adapter or a USB-C flash drive.

Step 3. Shut Down Your Mac

If your Mac is powered on, shut it down completely by clicking the Apple icon in the top-left corner of the screen and selecting "Shut Down."

Step 4. Boot Your Mac from the USB Drive

To boot your Mac from the USB drive, follow these steps:

1. Press and hold the power button to turn on your Mac.

2. Immediately press and hold the Option (or Alt) key on the keyboard. For Macs with Apple Silicon (M1 chip), press and hold the power button instead.

3. Release the Option key (or power button for M1 Macs) when the Startup Manager or boot options screen appears. This screen displays available bootable devices connected to your Mac.

4. Use the arrow keys or your mouse to select the bootable USB drive from the list of devices.

5. Press Enter (or click on the drive) to boot your Mac from the USB drive.

Step 5: Start Installing macOS from USB Drive

After booting your Mac from the USB drive, the macOS installer, recovery tool, or diagnostic utility should load. Follow the on-screen instructions to complete the installation process.

Frequently Asked Questions about macOS Installation

1. Can I reinstall macOS without losing my data?

Yes, you can perform a non-destructive installation that preserves your data and applications. However, it is strongly recommended to back up your data before proceeding.

2. Is it possible to downgrade macOS using a USB drive?

Yes, you can downgrade your macOS version if your Mac supports the older version. Create a bootable USB drive with the desired macOS version and follow the steps in this guide.

3. What if my Mac does not boot from the USB drive?

Check that the USB drive is formatted correctly and that the macOS installation file is not corrupted. Ensure you are using the correct key combination during startup.

4. Can I use a bootable USB drive created on a Windows PC to reinstall macOS on my Mac?

Yes, you can create a bootable macOS USB drive on a Windows PC using third-party tools such as TransMac or UUByte DMG Editor. The process remains the same as described in this guide.

Wrapping Up

Reinstalling macOS from a USB drive is a practical and efficient method for addressing various issues, enhancing performance, and ensuring system security. This guide has provided detailed instructions on how to prepare, create, and install macOS using a bootable USB drive. By following these steps, you can successfully reinstall macOS on your Mac while enjoying the advantages of using a USB drive over a direct upgrade.