How to create a Windows 10 USB Flash Drive installer from an ISO file

This article describes how to create a bootable USB flash drive for installing Windows 10 from the ISO file you already have downloaded. If you don’t have Windows 10 ISO file downloaded, head-over to our other step-by-step guide that shows how to download Windows 10 directly from Microsoft servers and create the USB installation drive.

Windows 10

For both the methods, you need to have an USB flash drive of at least 8 GB capacity (quite obvious!). The flash drive will be formatted during the process, so make sure you backup whatever you have in it.


The Easy Way using Rufus Free Utility

One of the simplest methods is to use a free program ‘Rufus’.

1. Download Rufus from here.

2. Launch the Rufus program.

3. Connect the USB flash drive to your computer.

4. Assuming that the USB installation disk is for use on a PC and not on Mac (without using Bootcamp Assistant), this is the settings that I recommend:

  • Partition scheme: MBR partition scheme for BIOS or UEFI
  • File System: NTFS
  • Volume Label: You can name whatever you want.
  • Make sure ‘Create a bootable disk using..’ is checked and since we are talking about ISO image, select ‘ISO Image’ from the drop-down list, click on the icon next to it, then browse and select the Windows ISO file that you have.
Windows 10 USB Media using Rufus

Windows 10 USB Media using Rufus

5. Click ‘Start’ and wait for the process to finish.

That’s it. You now have the Bootable USB disk which you can plug-in to your targeted computer and boot into it to start Windows 10 installation. Depending on your computer make and model you may have to configure BIOS to allow booting from USB.


Alternate Method: All Manual, No need of Third-party Software

If you prefer not to use any third-party tool to create the USB installer, you can still do it yourselves by simply using elevated Command Prompt.

1. Connect the USB flash drive to your computer.

2. Open ‘Command Prompt’ with Administrator rights. If you never used it, then you should probably not be using this method. I suggest to use the Rufus method shown above.

Elevated Command Prompt

Elevated Command Prompt

3. Type diskpart in the Command Prompt to open disk management utility.

Diskpart Utility

Diskpart Utility

4. Type list disk and hit enter to see all the writable media that you have on your PC. You should see your USB flash drive here which need to be identified by size. 7728 MB is typically 8 GB flash drive, shown in below image.


List Disk Command

List Disk Command

5.  As per your disk number, type select disk # and hit enter. In my example, # is 1. So I just type select disk 1 and hit enter.

Select Disk #

Select Disk #

6. It’s time to clean the USB flash drive, so type clean and hit enter.

Clean Disk

Clean Disk

7. We shall now create a bootable partition – to do that, type create partition primary and hit enter.

8. Select the partition that you just created – type select partition 1.

9. Type active and hit enter.

Commands

Commands

10. Next, we need to format the USB flash drive, so type format fs=ntfs and hit enter.

11. It’s good to assign a drive letter to it, so type type assign. As soon as you hit enter, you will see the explorer window of the USB disk showing empty content. Minimize it.

Format Disk and Assign

Format Disk and Assign

12. Close the command prompt.

13. Right-click on the Windows ISO file and ‘Mount’ it. If you don’t have ‘Mount’ in right-click context menu, then you might probably be using old version of Windows. Starting from Windows 8, mounting ISO image is built-in feature. Windows XP/Vista users can use a free third-party tool like SlySoft Virtual CloneDrive.

Mount Windows ISO image

Mount Windows ISO image

14. When the ISO is mounted, you can access all the files in it. Copy and paste all the contents into the empty USB disk that you just created.

Windows 10 ISO Contents

Windows 10 ISO Contents

You are done! Go ahead and try installing Windows 10 with this USB drive. Do let us know about how it worked out for you.

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Kiran Kumar

Hi there! Kiran Kumar is an Engineer by profession, and loves blogging primarily on Microsoft Windows operating system and also enjoys reviewing software and products. Currently, he is exploring Windows 10 and you will see a lot of articles on know-how about it. When he is not writing for TWP, he enjoys time with his Family, listens to lot of music, enjoys Biking, and occasionally plays racing games on Xbox One.