Install and boot Windows 10 / 11 on USB external disk

When developing software for PCs, multiple versions of an OS are needed for testing. In such cases, there is a way to install the OS on a virtual PC using VMware Workstation or other software. However, programs that use the GPU directly may require a physical machine. This article explains how to install Windows 10 or Windows 11 on an external disk.

Installing Rufus

To install Windows 10 or Windows 11 on a USB external disk in a bootable state, you can use an app called Rufus, available at the following site.

Rufus is OSS and licensed under the GPL. The code is available on GitHub.

GitHub

GitHub – pbatard/rufus: The Reliable USB Formatting Utility The Reliable USB Formatting Utility. Contribute to pbatard/rufus development by creating an account on GitHub.

The version used at the time of this writing is 3.2.1. After downloading, save it in a directory of your choice to complete the installation.

Installing Windows

Install Windows using Rufus. Connect the external disk where you wish to install Windows. Next, download the Windows ISO image. In my case, I used the ISO image provided with my Visual Studio subscription because I use it for software development and debugging.

Launch Rufus and follow the steps below to install.

STEP

Turn on “List USB Hard Drives”.

STEP

From “Device,” select the disk to install to.

STEP

Click the “SELECT” button and choose the ISO image of OS.

STEP

Enter the desired name for the destination disk in the “Volume label” field.

STEP

From “Image option”, select “Windows To Go”.

STEP

Click the “START” button.

STEP

インストールするWindowsの種類を選択します。

STEP

With “Prevent Windows To Go from accessing internal disks” turned on, click the “OK” button.

STEP

A confirmation message regarding the destination format will be displayed. Click “OK” to proceed.

STEP

Installation will start. When “READY” is displayed, the installation is completed.

Boot from an external disk

To boot from an OS installed on an external disk, adjust the BIOS or UEFI settings to give boot priority to the external disk over the internal one. Changing this setting depends on your machine, so please refer to the machine’s documentation.

Besides the boot disk priority, some machines also allow changing the priority of the UEFI boot manager. If your machine has this capability, adjust the boot manager’s priority to favor the external disk.