Creating a Windows bootable USB on a Mac can seem daunting, but don't worry, guys! It's totally doable, and I'm here to walk you through it step by step. Whether you need to install Windows on a PC, run Boot Camp, or troubleshoot a Windows machine, having a bootable USB is super handy. This guide is designed to make the process as smooth and straightforward as possible. Let's dive in!

What You'll Need

Before we get started, let's make sure you have everything you need:

• A Mac: Obviously! This guide is tailored for macOS users.
• A Windows ISO file: This is the disk image file of the Windows operating system. You can download it from Microsoft's official website. Make sure you have a valid product key if required.
• A USB drive: At least 8GB in size. Important: This process will erase everything on the USB drive, so back up any important data first!
• A stable internet connection: For downloading the necessary software and the Windows ISO file.
• Software: We'll primarily be using the Terminal, which comes pre-installed on your Mac. For some methods, you might need additional software like Homebrew or UNetbootin.

Having these items ready will ensure a smooth and efficient process. Now, let’s move on to the step-by-step instructions.

Method 1: Using Terminal (Command Line)

The Terminal is a powerful tool on macOS, and we can use it to create a bootable Windows USB. This method is a bit technical, but don't let that scare you! I'll break it down into manageable steps.

Step 1: Identify Your USB Drive

First, we need to identify the disk identifier for your USB drive. Open the Terminal (you can find it in /Applications/Utilities). Type the following command and press Enter:

diskutil list

This command will list all the connected drives. Look for your USB drive in the list. Take note of the IDENTIFIER for your USB drive (e.g., /dev/disk2). Be absolutely sure you identify the correct disk; otherwise, you could accidentally erase your hard drive!

Step 2: Unmount the USB Drive

Before we can format the USB drive, we need to unmount it. In the Terminal, type the following command, replacing /dev/disk2 with your USB drive's identifier:

diskutil unmountDisk /dev/disk2

This command unmounts the disk, making it ready for formatting.

Step 3: Format the USB Drive

Now, we'll format the USB drive to FAT32, which is compatible with Windows. Use the following command in the Terminal, again replacing /dev/disk2 with your USB drive's identifier:

sudo diskutil eraseDisk FAT32 "WINDOWS10" MBRFormat /dev/disk2

• sudo gives you administrator privileges.
• diskutil eraseDisk is the command to erase and format the disk.
• FAT32 is the file system format.
• "WINDOWS10" is the volume name for the USB drive (you can change this).
• MBRFormat specifies the Master Boot Record format, which is compatible with most PCs.

Important: You'll be prompted to enter your password. Type it in and press Enter. Note that you won't see the password being typed in the Terminal.

Step 4: Copy Windows Files to the USB Drive

Now, mount the Windows ISO by double-clicking on it. This will mount it as a virtual drive.

Use the rsync command to copy the files from the mounted ISO to your USB drive. In the Terminal, type the following command. You may need to adjust the paths to match your mounted ISO and USB drive. First, locate the mount point of the ISO and the USB drive. They will typically be in /Volumes. Then run the command:

rsync -v -a --exclude=Sources/install.wim /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WINDOWS10

• -v enables verbose mode, so you can see the files being copied.
• -a archives the files in a way that preserves permissions and other metadata.
• --exclude=Sources/install.wim is crucial because the install.wim file is often too large for FAT32. We'll handle this separately.

This process may take some time, depending on the size of the ISO file and the speed of your USB drive. Wait for it to complete. If you encounter any errors, double-check the paths and permissions.

Step 5: Splitting the install.wim File (If Needed)

This step is only necessary if the install.wim file is larger than 4GB. FAT32 has a file size limit of 4GB, so we need to split the file into smaller chunks.

First, install wimlib using Homebrew. If you don't have Homebrew installed, you can install it by following the instructions on the Homebrew website.

Once Homebrew is installed, run the following command in the Terminal:

brew install wimlib

After wimlib is installed, use the wimsplit command to split the install.wim file. Navigate to the Sources directory inside the mounted ISO image. Then run this command, adjusting the paths as needed:

wimsplit /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim /Volumes/WINDOWS10/sources/install.swm 4000

• /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim is the path to the original install.wim file.
• /Volumes/WINDOWS10/sources/install.swm is the destination and the base name for the split files. They will be named install.swm, install2.swm, etc.
• 4000 is the maximum file size in MB (4000MB = ~4GB).

This will split the install.wim file into smaller .swm files that can be stored on the FAT32 USB drive.

Step 6: Eject the USB Drive

Once the files are copied and the install.wim file is split (if necessary), eject the USB drive. In the Terminal, type:

diskutil eject /dev/disk2

Replace /dev/disk2 with your USB drive's identifier. You can also eject the drive from Finder.

Your Windows bootable USB drive is now ready! You can use it to install Windows on a PC or use Boot Camp on your Mac.

Method 2: Using UNetbootin

UNetbootin is a graphical tool that makes creating bootable USB drives much easier. It's a great option if you're not comfortable using the Terminal.

Step 1: Download and Install UNetbootin

Go to the UNetbootin website and download the macOS version. Once downloaded, open the DMG file and drag the UNetbootin application to your Applications folder.

Step 2: Launch UNetbootin

Open UNetbootin from your Applications folder. You might see a warning about opening an application downloaded from the internet. Click