How to make a bootable Windows 10 USB stick on a Mac the easy way

You are here because you want to create a USB stick to install Windows 10 but you only have a Mac at home. You have tried every different method imaginable and nothing seems to work.

After a lot of trial and error, I have found a straightforward method that works every time. The only drawback is that it requires some additional disk space in your Mac.
But before we get to the actual solution, let me just give you a quick overview of the different methods I tried before getting to this solution.

Nothing worked for me

I tried every different method described on the world wide web and all failed.

Just to name a few:

  1. I tried to create a USB stick to install Windows using Bootcamp. Not only you need to have an old version of Macos X for this to work, but even if you do have one, at least in my case, it didn’t work. I was able to create the USB stick but it wouldn’t boot on my new PC.
  2. Using software utilities like UNetbootin, highly discouraged by Apple with some scary warnings, from doing so, also didn’t work for me.
  3. Some convoluted methods that require me to use diskutil either from the command line or from the UI, also no luck. 
  4. I have even seen articles suggesting to use rsync! Come on, if I want to install windows, I definitely do not want to resort to Rsync

Why is it so hard to create a USB stick to install Windows 10

The main reason why it is so hard to create a Windows USB stick from a Mac has to do with file size limits on the FAT32 file system(4 GB). The latest Windows 10 install has a file with 5GB, so if you try to copy the install files to a USB stick, it will fail because one file is over 4GB size. 

Some of the solutions to this problem propose using ExFAT instead, as it accepts file sizes above 4GB. However, my BIOS will not boot from a USB flash drive formatted with ExFAT. So I am stuck with FAT32.

To make FAT32 work you need to split the file which is bigger than 5GB into chunks under the file size limit. Yes, you can eventually make it work. But this is far too time-consuming. There is a much easier way!

How to create a USB stick to install Windows from Windows

After all this struggle I realized that there must be an easier way to create a USB stick to install Windows from a Mac. And the solution involves using Windows itself.

Hang on, how can we use Windows to install Windows if we don’t have windows?

Installing Windows on a Mac using Bootcamp

Even though it might seem counter-intuitive to install Windows on a Mac just to create a Windows 10 install on a USB stick, this was the simplest solution I could find. And there is no trial and error. This method will work every time. And at the end, you can delete the Windows partition and reclaim the space again for use on your Mac.

Prerequisites

Before you can start, you will need to have plenty of disk space available on your Mac to make some space for the Windows Partition. In my case, Bootcamp reserved 64GB for the windows partition. In theory, 100GB of space should be enough.

Download Windows 10 ISO

Download the Windows ISO from https://www.microsoft.com/en-gb/software-download/windows10ISO. Make sure you don’t let more than 24h elapse, as the download will expire.

After you finish the download, start Bootcamp.

You can increase and decrease the size of your Windows 10 Partition with the slider, but the minimum partition size allowed for Windows is 64GB.

Installing Windows 10 on your Mac

Once you click install, Bootcamp will start the installation process for you. You will be asked to enter a license key during the install process. Don’t enter it yet! The install process will work without the license key.

You are only installing Windows on your Mac to create a USB stick install of Windows 10. If you enter your license key now your license key will be tied into your Mac and you won’t be able to use it later when you install Windows 10 on your actual PC. 

If you plan to use Windows 10 indefinitely on your Mac, then by all means enter a license key here.

Using the Windows Media Tool

Once you boot into Windows using Bootcamp, and after you complete the installation process, you can go back to the Microsoft website and download the Windows Media Tool:

You should see a link “Download tool now” from the Microsoft windows 10 install website as shown in the screenshot above.

After downloading and going through the installation process of the Windows Media Tool, start it and you should see a similar screen to the below:

Select the option “Create installation media USB disk…” and click “Next”.

Unless there’s something wrong, click Next. At this stage you should connect your USB Flash drive to your computer.

Choose USB flash drive and click “Next

Check that the correct USB flash drive is selected. and click Next.

And voila, you should see this:

Yes I know, it is downloading Windows again. But at least you can be confident 100% that your flash drive will install Windows on your shining new PC!

Long live Windows! Bye Mac!

Hope you found this article useful. It makes it any easier watch my video on Youtube which shows me following the same steps I have just described: