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.
Not dissing the shell, but I’ve found etcher pretty reliable for writing usb install media and has a decent ui – https://www.balena.io/etcher/
This tool throws an error when trying to flash a Windows image from a mac
The tutorial is great, thank you, but I had an issue:
One file’s size (/sources/install.wim, in the 64 bit version) is greater than 4 GB, so will not fit in your MS-DOS formatted partition. How do you go around it?
I retried everything replacing MS-DOS with ExFAT, but then the target computer doesn’t allow to boot from that USB stick.
Also, note that if you run at the very end:
cp -rpv (with the “v” added), you see progress!
Hi
I’ve run into the same problem – did you find a workaround?
I found this workaround helpful (https://alexlubbock.com/bootable-windows-usb-on-mac), the below steps are a summary of the relevant ones from the linked page.
1. Copy the files (that fit, eg exclude the install.wim) onto the usb (using rsync can also show the progress in comparison to the ‘cp’ command’
rsync -avh –progress –exclude=sources/install.wim /Volumes/CCCOMA_X64FRE_EN-US_DV9/ /Volumes/WINDOWS10
2. Install Homebrew (skip if you already have Homebrew installed)
/usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)”
3. Install WimLib
brew install wimlib
4. Split the install.wim file, and store it on the USB
wimlib-imagex split /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim /Volumes/WINDOWS10/sources/install.swm 4000
Thanks a lot, this helped a lot only issue was install.wim file 4.61gb being too large for FAT32 to work it with UEFI boot – resolution for that can be found here – https://www.dell.com/support/article/us/en/19/sln313422/windows-10-iso-contains-wim-file-that-is-big-for-fat32-file-system?lang=en
I just used split into two svm files solution. thanks
Thanks a lot, this helped a lot only issue was install.wim file being too large for FAT32 to work it with UEFI boot – resolution for that can be found here – https://www.dell.com/support/article/us/en/19/sln313422/windows-10-iso-contains-wim-file-that-is-big-for-fat32-file-system?lang=en
I just used split into two svm files solution. thanks