Whether you are dual-booting your Mac or formatting a new PC, the best way to get Windows 10 is through a fresh installation, not an upgrade. But you'll need to create a bootable Windows 10 USB drive first. The process is a little more complicated if you're using a Mac.

Microsoft offers a simple tool to create a bootable USB on Windows, but there is no such tool for Mac users. The process can be easy or relatively complicated depending on which type of Mac you have. We'll explain the differences below.

What You Will Need Before You Start

You'll need the following things to create a bootable Windows 10 installer:

  • An 8GB or larger USB drive whose data you don't mind losing. You can pick up a new 8GB drive for as little as $5.
  • Your MacBook power adapter should be plugged in. You don't want the laptop running out of battery in the middle of creating the bootable drive.
  • This method obviously requires a valid Windows 10 license to activate the operating system.
  • An active internet connection, to download any updates required.

Download the Windows ISO

Microsoft has free downloadable ISO files for Windows 10 on the official Microsoft website. Select Windows 10 from the edition menu, choose your language, and download the ISO file depending on which version of Windows you want to install (32-bit or 64-bit).

Once you have downloaded the ISO, keep it in a location you can easily find later, like your desktop or downloads folder.

Plug in Your USB Drive

Image of an 8GB USB drive.

Disconnect any other USB hard drive, optical drive, or other storage media you have connected.

The process to create the bootable USB is different on Intel and M1 Macs. We've detailed both processes below.

How to Create a Bootable Windows 10 USB on Intel Macs

The process to create a bootable Windows 10 USB installation disk is quite easy on Intel-based Macs since they support Boot Camp. macOS's built-in Boot Camp Assistant can be used to install Windows on Mac and create a bootable USB installer drive, eliminating the need for third-party apps.

Boot Campt Assistant in Spotlight search

To start Boot Camp, press Cmd + Space to bring up Spotlight, type "Boot Camp Assistant" (without the quotes), and press Enter.

Click Continue in the introduction dialog box.

Configure Boot Camp

Check the box for "Create a Windows 7 or later install disk".

Boot Campt Assistant task selection.

The other options will probably be grayed out, but in case they aren't, check the second box for Download the latest Windows support software from Apple, and don't check the third box.

Click Continue when done.

Choose Your ISO Image and USB Drive

Browse to and select the Windows 10 ISO file you downloaded.

Boot Camp Assistant disk selection.

Under Destination Disk, make sure you see your USB drive.

Click Continue when done.

Copy the Image to the Disk

Boot Camp will format your USB drive so, again, make sure it has no important data on it that you can't afford to lose. All the data will be wiped.

Boot Camp Assistant warning message.

Click Continue to proceed. The installation process will now start and you won't need to interact at all. Just let it run.

Boot Camp Assistant proress bar.

If you're on a MacBook, don't shut the MacBook's lid. It's an instinctive act that several of us do when we aren't using the laptop, but this will put your Mac to sleep and interrupt the process.

When everything is done, you'll see a window that says The Windows support software has been saved.

Boot Camp Assistant completion screen.

Click Quit to finish your procedure, then unmount and unplug your USB drive. Congratulations! This is now a bootable Windows 10 installer.

How to Create a Bootable Windows 10 USB on M1 Macs

The process to create a bootable disk is slightly more complicated on M1 Macs. This is due to the limitation of ARM-based chips not being able to natively support the full version of Windows. Hence, Apple does not include Boot Camp Assistant on M1 Macs, which means you'll have to resort to another method to create a bootable disk.

Another major issue faced when creating a bootable disk on Macs is the limitation of burning a larger-than-4GB file on a FAT32 formatted drive. Windows and macOS only have the FAT32 file system in common, which can only store a single file of less than 4GB. Since the install.wim file included in the Windows 10 installer is around 4.79GB, this creates an problem.

A workaround for this issue is splitting the installer into smaller files, and then combining them later. For this, you'll need to install Homebrew on your Mac. Homebrew is an open-source software package manager that we'll use to add a command-line tool called wimlib. This will split the Windows installer file while creating the bootable disk.

Related: What is Homebrew? How to Install Mac Apps in Terminal Using Homebrew

To install Homebrew and create a bootable Windows 10 USB, go to Finder > Applications and launch Terminal. Enter the following commands and press Enter—this will install Homebrew on your Mac:

curl -fsSL -o install.sh https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh

/bin/bash install.sh

Install HomeBrew Using Terminal

The process may take a few minutes to complete, depending on your internet connection. It will download and install Xcode before installing Homebrew. Xcode is an integrated development environment (IDE) that is comprised of software development tools for macOS.

Type in your Mac user password to authenticate yourself and press Enter to install Homebrew. Once the installation is complete, enter the following command and press Enter to install wimlib:

brew install wimlib

In the case you get an error message command not found:brew, you may see two commands in Terminal right at the end of the previous Homebrew installation. Enter the commands to activate Homebrew, and then enter the command above again to get it working successfully.

Commands to Activate HomeBrew

Make sure your USB stick is connected to your Mac. Type diskutil list and press Enter in Terminal to bring up a list of all drives connected to your Mac. Note down the USB stick's disk identifier—disk2, disk3, disk4, etc. It should appear to the left of (external,physical) as shown below.

Disk Identifier in Terminal

If you're unable to recognize the USB disk in Terminal, try identifying it using the Size column.

Use the following command to format the USB stick (replace disk2 with your disk identifier):

diskutil eraseDisk MS-DOS WINDOWS10 GPT /dev/disk2

This will erase the USB disk and rename it to WINDOWS10, which will be easier to distinguish at later stages.

Mount the Windows 10 ISO from the Downloads folder of your Mac. You can do this by double-clicking on the ISO file, which should then show up in the connected devices with the name CCCOMA_X64FRE_EN-US_DV9. Alternatively, you can also do this in Terminal with the command below, but make sure to replace the file name and path as needed:

hdiutil mount ~/Downloads/Win10_21H1_English_x64.iso

Use the following command to copy the content of the ISO image—excluding the install.wim file—onto the USB drive:

rsync -vha --exclude=sources/install.wim /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WINDOWS10

Enter the following command to split and copy the install.wim file to the USB stick:

wimlib-imagex split /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim /Volumes/WINDOWS10/sources/install.swm 3000

Windows 10 Command

That's it! Once Terminal has successfully created the bootable disk, simply unmount the USB from the desktop and use it to boot a Windows installation.

While Booting: USB vs. UEFI

When you go to install Windows 10 on a PC with this USB drive, your motherboard might not boot with it, even if you have set to boot with the USB first. It's a common problem with a simple solution.

Go to your motherboard's BIOS settings by tapping F2 or Delete as it powers on. In the Boot settings, you will likely see two options for your USB drive that seem similar, titled something like USB Mass Storage Device and UEFI USB Device.

BIOS Boot for Windows 10.

Choose UEFI instead of USB Mass Storage. Save the new settings, exit BIOS, and restart. This time, your computer should boot into your Windows 10 installer USB drive.

UEFI is a type of firmware for motherboards instead of the traditional BIOS, and BCA uses it by default when creating USB installation media. It makes no real difference to a regular user, so just change the setting and you're good to go.

Related: How to Install Windows 10 From a Bootable USB Drive

Try Getting Your Hands on a Windows Machine

With all of these options, you should be able to make Windows 10 installation media on your Mac. With the process being quite complicated as detailed above, we'd recommend just borrowing a friend's Windows laptop to create the bootable disk, which is a lot simpler. If that's not possible for you, you can create a Windows bootable disk on your Mac using the guide above.