How To Create Windows 10 Install Media In macOS Mojave

Image: Microsoft

I was recently tasked with setting up a Windows 10 system for a friend on an oldish laptop. While the machine is about five years old, it does have an SSD and ran Windows 7 and 8 pretty well. So, I needed to create installation media for the system. But, as my main system is a Mac I needed to find a way to create a bootable USB or SD Card. Here's how I did it.

Back in the day, Apple made it reasonably easy to create bootable USB storage and SD cards using graphical tools. But that capability disappeared a couple of years ago. Fortunately, you can do everything you need using the Terminal program and a couple of simple commands.

#1 Download The Windows 10 ISO Image

You can download Windows 10 installation media images from Microsoft free of charge but note that you will need an installation key which you'll need to procure (legally) from a legitimate source.

Go to the offical download site, choose the edition you need and the correct language version and download.

#2 Prepare your installation media

While the download is happening, pop an 8GB USB or SD card into your Mac and type the following command.

diskutil list

This will list the various drives connected to your Mac.

Identify the one that you'll be using for the Windows 10 installation media. You'll be able to do that by looking at the list and closing the volume by its size.

Take note of which disk number it is.

#3 Format The Disk

While you're in Terminal, enter the following command:

diskutil eraseDisk MS-DOS "WINDOWS10" MBR disk2

Make sure you use the disk number corresponding to the card or USB stick you'll be using in place of the "disk2" part of the command.

#4 Open The Windows 10 ISO

Once the Windows 10 ISO is downloaded - it may take a while as the files are between 3.5GB and 6GB depending on whether you've chosen the 32-bit or 64-bit versions - double-click the file.

That will mount the ISO as a volume on your Mac.

#5 Copy The Files To Your USB or SD Card

In order to copy the files to the storage device so that it's bootable, you'll have to use the Terminal again. The process won't work if you use the Finder to drag and drop the files.

If you've downloaded the 32-bit version of Windows 10, use the following command to copy the files. Note that you may need to change the "CCCOMA_X86FRE_EN-US_DV9/" section if you've downloaded a different language version of Windows 10. The command below refers to the US English version.

cp -rp /Volumes/CCCOMA_X86FRE_EN-US_DV9/* /Volumes/WINDOWS10/

For the 64-bit version (noting any differences if you've used the non US English version):

cp -rp /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WINDOWS10/

This process will take a while and will look like nothing is going on. Be patient. It may take over 15 minutes depending on the speed of the media you're using.

Once that completes, you'll be able to install Windows 10 from the installation media you've created.