How Can I Burn Windows ISO to USB on Mac M3?

MikeLaba wrote:

Creating a Windows 10 virtual machine on Mac M3 is another option to burn ISO to USB on Mac. However, it is a bit complicated.

By using virtualization software like Parallels Desktop or VMware Fusion, you can run Windows 10 on your Mac.

On an Apple Silicon Mac, Parallels Desktop creates ARM virtual machines, not Intel ones. You cannot install Intel versions of Windows.

You can install Windows 11 for ARM, and it can run some Windows/Intel applications, but there are limitations and there is overhead because of the need to simulate a different machine code instruction set.

Unlike Intel-based Macs, which natively support Boot Camp for burning Windows ISO to USB, Apple Silicon Macs do not offer this utility. This means users must rely on third-party tools, which can be less intuitive and may require additional steps to work correctly with Apple’s new architecture. Furthermore, the compatibility of Windows on ARM with these tools is often inconsistent and lead to potential difficulties during the installation process.

One of the significant challenges in burning Windows 10 or Windows 11 ISO on a Mac is dealing with the large size of the install.wim file, which often exceeds 4 GB. This poses a problem because the FAT32 file system, typically used for bootable USB drives due to its compatibility with most UEFI systems, has a maximum file size limit of 4 GB. As a result, the install.wim file cannot be saved on a FAT32 partition. In addition, Mac does not support writing to NTFS drive by default, no matter it is an old Intel Mac or newer Apple Silicon M1/M2/M3 Mac.

To overcome this limitation, a common workaround is to split the install.wim file into smaller parts that can fit within the FAT32 file size limit or to format the USB drive. Therefore, creating a Windows 11/10 bootable USB on a Mac involves more steps and a deeper understanding of file systems and boot mechanisms.

As you pointed out, the install.wim file can easily blow past that pesky 4 GB limit if you're using FAT32. This is a real pain because it requires some extra steps to deal with splitting the file or finding workarounds. It's pretty frustrating to go through all the effort of burning Windows ISO to USB on Mac M3, only to find you can't fit the entire install file on it without some hacks.

One time, I thought I could squeeze a hefty ISO onto a smaller USB stick. Yeah, that didn't go well. Make sure your USB drive has enough space for the entire ISO file – otherwise, you'll hit a dead end.

If you're using Terminal to burn Windows ISO to USB on Mac M3, it's easy to forget to set the USB as bootable. I overlooked this detail a couple of times, then found myself staring at my screen, wondering why the USB wasn't booting. It's crucial to follow the steps precisely to avoid this hiccup.

If you plan to install Windows later, check that your Mac's hardware and the ISO you're using match up. I remember trying to run a Windows version on newer hardware and hitting compatibility issues. Just double-check everything before you burn Windows ISO to USB on Mac M3.

Especially if you're switching between OSes, sometimes you forget that you need the proper drivers to recognize devices fully. I booted into Windows once only to find out the USB wasn't recognized. A bit of a nightmare, to say the least!

Creating a Windows 10 virtual machine on Mac M3 is another option to burn ISO to USB on Mac. However, it is a bit complicated.

By using virtualization software like Parallels Desktop or VMware Fusion, you can run Windows 10 on your Mac. It provides access to the full range of Windows tools and applications. This setup is particularly useful for tasks that are more easily accomplished on Windows, such as using specialized software for burning ISO to a USB on Mac. The process of creating the virtual machine is straightforward, and once set up, it allows you to perform the ISO burning task (Windows Media Creation Tool) without the need for a physical Windows PC.

I just did the following with a sacrificial 32 GB USB stick:

I wanted to see what device the mounted USB stick named "STUFF" was mounted to:

diskutil info /Volumes/STUFF | awk '/Node:/ {print $3}'
/dev/disk5

Now I want to format that drive as exFAT (with its hidden EFI partition). The drive name Win11 will get changed later to Microsoft's naming:

diskutil eraseDisk "exFAT" Win11 MBRFormat /dev/disk5

Now, it needs to be unmounted or will report that it is in use and cannot be written to:

diskutil unmountDisk /dev/disk5

and now we write the Win 11 ISO to the USB stick without FAT32 4GB file size limitations. This would be an ARM version of Win 11 for Apple Silicon Macs. Count on this taking a few minutes.

dd if=/Users/$USERNAME/Downloads/Win11_22H2_English_x64v1.iso of=/dev/rdisk5 bs=1m

When the dd copy is done, eject the USB stick

diskutil eject /dev/disk5

When I remounted this USB stick and told Parallel's Desktop to associate it to the current virtual machine, it became drive D in Windows 11 Pro with the name (CCCOMA_X64FRE_EN-US_DV9) and clicking the Setup tool on the drive did what you would expect for Windows 11 Pro, ask if it was OK to proceed.

Give this a whirl using the instructions for the dd utility: https://techcommunity.microsoft.com/t5/windows-11/how-can-i-create-windows-11-bootable-usb-on-mac/m-p/4191173