How to create a bootable Windows 10 USB on Mac

The last release of Mac OS doesn’t have the option to create a bootable USB from Bootcamp like previous versions, and it is a problem because that require uses other tools.

I am updating this post today Dec 12, 2018. The reason is that I was only using UNetbootin to create the bootable USB, I will leave guide as a second method since it still working, and I will explain to you how you can create the bootable Windows USB without extra software.

The first step for both methods requires to format your USB device to NTFS, this is the default filesystem, alternative you can use ExFAT but the installation could fail.

Format USB to ExFAT (Under your own risk)

In order to boot from the USB, you need to format the USB to ExFAT, you can do it using Disk Utility (it comes with MacOS).

This step is the same for both methods. You need to show all the devices in Disk Utility» before to start the process.

Select your USB device in the list (not the partition), right click and then click on the Erase option:

In the next screen make sure you select these two options:

• Format: ExFAT
• Scheme: Master Boot Record

Click the Erase button.

If for some reason it fails, probably is because MacOS still using the USB, just repeat the steps, but if you see a screen similar to above screen is because the operation is successful.

Format USB with the terminal

You also can format the USB from the terminal, but you have to take care to use the correct device because, if you use the wrong name you will lose everything.

With this command you can list the device on MacOS:

This is an example, my USB is the disk2:

This command is to format the USB, the last parameter is the the USB:

Copy Windows files to USB — Method 1

This process is very easy doesn’t require to install other software, and they are just a few steps:

Open Windows ISO

Just double click on the ISO image, MacOS mount the image automatically.

Copy files

Now you only need to copy the files and paste them to the USB.

• Command + A Select all files.
• Command + C Copy files.
• Go to your USB Command + V paste the files.

This process could fail if you are using a USB with FAT32 because the file install.win is over 4GB, if this is the case try to open the terminal and copy paste the files from there (no always works. Try to follow the instructions to format the USB in ExFAT, NTFS works for some BIOS).

This is the command to copy the files from the ISO to the USB:

And that is all, now you can try boot from the USB.

UNetbootin — Method 2

I will show you how you can use UNetbootin to create a bootable USB, it can be used no only for Mac but for Windows and Linux distributions too.

UNetbootin is free software and it is also available for Windows and Linux.

Check the path name of your USB Disk.

Always in Disk Utility, select the new partition that we created in the previous step, and click on the information button, it will give you the information about the new partition.

You also can use the terminal and the command diskutil to see the list of drives:

Download UNetbootin:

Download the dmg directly from the Website.
And copy the app to the /Application folder.

I prefer to use homebrew to install applications, you can check this article for more information: Installing Applications on Mac with Homebrew:

Makes the USB booteable

Open UNetbootin and you only need select 3 options:

• Diskimage and ISO
• Now we need open the ISO Windows image that is on our computer.
• Select your USB device on UNetbootin.
• Click on the OK, button and wait to the process end it will take a time.

NOTES:

• I tested other tools like dd and Etcher but they are not working because Windows requires extra steps, for the moment this is the only easy tool that I know that works if you are on Windows try Rufus.
• Some users reported that UNetbootin is not working, if after to format the USB drive and change the block size is not working for you try another Drive with enough space.

Creating bootable USB from ISO in MacOS

macOS High Sierra

I needed to reinstall one of my Windows PCs at home recently, and realised that I only have Windows 7 DVDs, but no Windows 10s.

Since it’s possible to boot and install Windows 10 from USB, that’s what I decided to do: download Window 10 ISO and burn it one of the USB sticks I have. This approach will be simpler for any other ISO image like Ubuntu or CentOS, so there’s a separate Steps 3-5 for them at the end of the post.

Here are the steps I had to take on my MacBook, originally procedure was written in macOS High Sierra, but I tested it in MacOS Mojave 10.14.2 as well. All of these need to be done in the Terminal app.

Windows 10 bootable USB vs Linux ISO USB

Windows 10 is a very specific bootable media, so the process is a bit involved. For generic Linux installation ISOs this procedure would be simpler. So the first two steps are the same, then Windows and Linux have separate procedure.

Here’s what we will do for Windows ISO:

• erase USB stick and create MBR (master boot record)
• format USB stick with FAT-32 filesystem
• mount Windows 10 ISO image as a folder
• copy all the files from that folder onto the USB stick

Here’s what we would do for Linux ISO:

• use dd command to burn Linux installation ISO onto USB stick

Step 1: Confirm partitions before inserting USB

Use the diskutil command to list all disks and partitions on your Mac. This is simply so that you can run the same command again after inserting USB and easily spot the USB device.

Step 2: Insert USB stick an re-run diskutil list

This time I can see there’s a disk9 showing up, with 64GB of size which matches my USB stick size:

Chances are, your USB stick has a PC standard FAT16/FAT32 filesytem, and will be mounted automatically. Let’s check:

Sure enough, it’s mounted as /Volumes/NONAME!

Creating Windows bootable USB

IMPORTANT: these steps are only needed for Windows ISOs. If you’re burning a Linux ISO, skip this and go to the Creating Linux bootable USB section below, it has its own steps.

Step 3: format USB stick for Windows boot

This single command will erase the USB stick, make it bootable by adding a Master Boot Record (MBR) and create a Windows-friendly filesystem (FAT) on it:

You’ll have the new filesystem mounted automatically, as you can see it’s empty (1.1MB used of 14GB):

Great stuff, now we’re moving to the next phase: we need to mount the Windows ISO image as a folder and then copy all the files onto the freshly formatted /Volumes/WIN10 USB stick.

Step 4: Mount Windows ISO

Simply go to the directory where you have the ISO image and run the open command for it:

You’ll have the MacOS Finder window with Windows ISO content pop-up, just ignore it and go back to the terminal.

You should now have it mounted under folder like this:

Go into that folder and do ls to make sure you can see Windows DVD files there:

Step 5: Copy Windows files onto USB stick

Right, now we have to copy all the files from DVD ISO image onto our new USB stick.

IMPORANT: you should be in the /Volumes/CCSA_X64FRE_EN-US_DV5 directory when running this command below. That’s exactly where you are if you just completed Step 4.

The copy will take good 10-15min:

There should be no errors returned.

If you remember, in Step 3 we did the df command and the USB filesystem /Volumes/WIN10 was empty.

Just to get an idea that the copy was successful, let’s run the df command again to make sure the USB stick has roughly the same amount taken up now – 4.1GB as per output fragments in previous step.

Looks good! What’s left now is to eject the USB stick:

and to boot it on the PC as shown below.

Step 6: Boot USB stick on your PC

IMPORTANT: recent enough PCs will likely offer you both legacy boot and UEFI boot. The rule of thumb is to boot UEFI if it’s available, especially if you’re booting Windows USB stick:

Creating Linux bootable USB

As I said earlier, non-Windows ISOs are much easier to deal with! So after the first 2 generic steps at the start of this post, we’ll be taking separate steps for Linux as shown below.

We need to unmount the USB disk we found in Step 2. It’s /dev/disk9 in our case:

Step 3: convert ISO into bootable DMG

WARNING: this is an important step, without it your USB stick won’t boot.

So I have this DVD ISO of the CentOS 7.4, let’s convert it before burning onto the USB stick.

Step 4: write DMG image onto USB stick with dd

Exellent, now we are ready to burn the ISO image. Let’s cd into the directory with all the ISOs that you have and burn it using the dd command.

dd command runs with the help of 3 command line parameters:

• if – specifying source data, that’s our ISO image file
• of – specifying the destination file or device, /dev/disk9 in our case
• bs – block size, just needs to be something big enough like 1m (meaning 1 megabyte)

Depending on the ISO size and the USB stick speed, you’ll have to wait 10-20min for this to complete.

Useful tip (cheers Jim!): if you want to confirm your current process, press Ctrl+t in the Terminal app and it should update output with dd progress (I highlighted the output below every tipe I pressed Ctrl+t):

finally, dd will complete a message like this:

Step 5: Boot USB stick on your PC

That’s it, we’re done! Eject the USB stick (no need to run any diskutil commands as it wasn’t mounted automaticaly) and boot on your PC.

IMPORTANT: recent enough PCs will likely offer you both legacy boot and UEFI boot. The rule of thumb is to boot UEFI if it’s available:

How to Make a Windows 10 USB Using Your Mac — Build a Bootable ISO From Your Mac’s Terminal

Quincy Larson

Most new PCs don’t come with DVD drives anymore. So it can be a pain to install Windows on a new computer.

Luckily, Microsoft makes a tool that you can use to install Windows from a USB storage drive (or «thumbdrive» as they are often called).

But what if you don’t have a second PC for setting up that USB storage drive in the first place?

In this tutorial we’ll show you how you can set this up from a Mac.

Step 1: Download the Windows 10 ISO file

You can download the ISO file straight from Windows. That’s right — everything we’re going to do here is 100% legal and sanctioned by Microsoft.

If you want an English-language version of the latest update of Windows 10, you can download the ISO here.

If you have a relatively new computer, you probably want the 64-bit version. If you’re not sure, go with the 32-bit version to be safe.

If you want a non-English-language version of Windows, or want to get an older update version, download the ISO here instead.

Step 2: Insert your USB storage drive into your Mac

The ISO file is only about 5 gigabytes, but I recommend you use a USB drive with at least 16 gigabytes of space just in case Windows needs more space during the installation process.

I bought a 32 gigabyte USB drive at Walmart for only $3, so this shouldn’t be very expensive.

Stick your USB drive into your Mac. Then open your terminal. You can do this using MacOS Spotlight by pressing both the ⌘ and Space bar at the same time, then typing «terminal» and hitting enter.

Don’t be intimidated by the command line interface. I’m going to tell you exactly which commands to enter.

Step 3: Use the diskutil command to identify which drive your USB is mounted on

Open Mac Spotlight using the ⌘ + space keyboard shortcut. Then type the word «terminal» and select Terminal from the dropdown list.

Paste the following command into your terminal and hit enter:

You will see output like this (note — your Mac’s terminal may be black text on a white background if you haven’t customized it).

Copy the text I point to here. It will probably be something like

Step 4: Format your USB Drive to work with Windows

Next format your USB drive to Windows FAT32 format. This is a format that Windows 10 will recognize.

Note that you should replace the disk2 with the name of the your drive from step 3 if it wasn’t disk2 . (It may be disk3 or disk4 ).

Run this command using the correct disk number for your USB:

diskutil eraseDisk MS-DOS «WIN10» GPT /dev/disk2

Then you’ll see terminal output like this.

This will probably only take about 20 seconds on a newer computer, but may take longer on an older computer.

Note that for some hardware, you may instead need to run this command, which uses the MBR format for partitioning instead of GPT. Come back and try this command if step 7 fails, then redo steps 5, 6, and 7:

Step 5: Use hdiutil to mount the Windows 10 folder and prepare it for transfer.

Now we’re going to prep our downloaded ISO file so we can copy it over to our USB drive.

You will need to check where your downloaded Windows 10 ISO file is and use that. But your file is probably located in your

/Downloads folder with a name of Win10_1903_V1_English_x64.iso .

Step 6: Copy the Windows 10 ISO over to your USB Drive

Update April 2020: One of the files in the Windows 10 ISO – install.wim – is now too large to copy over to a FAT-32 formatted USB drive. So I’ll show you how to copy it over separately.

Thank you to @alexlubbock for coming up with this workaround.

First run this command to copy over everything but that file:

rsync -vha —exclude=sources/install.wim /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WIN10

Then run this command to install Homebrew (if you don’t have it installed on your Mac yet):

/usr/bin/ruby -e «$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)»

Then use Homebrew to install a tool called wimlib with this terminal command:

brew install wimlib

Then go ahead and create the directory that you’re going to write the files into:

Then run this command. Note that this process may take several hours, you may see 0% progress until it finishes. Don’t abort it. It will use wimlib to split the install.wim file into 2 files less than 4 GB each (I use 3.8 GB in the following command), then copy them over to your USB:

wimlib-imagex split /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim /Volumes/WIN10/sources/install.swm 3800

Once that’s done, you can eject your USB from your Mac inside Finder. Note that Windows will automatically rejoin these files later when you’re installing.

Step 7: Put your USB into your new PC and start loading Windows

Congratulations — your computer now should boot directly from your USB drive. If it doesn’t, you may need to check your new PC’s BIOS and change the boot order to boot from your USB drive.

Windows will pop up a screen and start the installation process.

Enjoy your new PC, and your newly-installed copy of Windows.

Quincy Larson

The teacher who founded freeCodeCamp.org.

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