WinToUSB 4.0

WinToUSB (also called Windows To USB) is the best free Windows To Go Creator which allows you to install and run a fully-functional Windows operating system on an external hard drive or a USB flash drive. It is so easy and efficient, with just a few simple steps and a few minutes, you can create your first portable Windows 10/8/7 directly from an ISO, WIM, ESD, SWM, VHD, VHDX image file or a CD/DVD drive, or you can use it to clone an existing Windows OS installation (Windows 7 or later) to a USB drive as portable Windows. WinToUSB also supports creating a Windows installation USB flash drive from a Windows 10/8.1/8/7/Vista/2016/2012/2010. Oh, WinToUSB also supports creating a bootable Windows PE USB drive, it can help you transfer the contents of Windows PE to a USB drive and make the USB drive bootable.

WinToUSB's key features include:
Easy-to-use wizard interface that provides step-by-step instructions for creating a Windows To Go USB drive.
Creation of Windows To Go from an ISO/WIM/ESD/SWM image file or CD/DVD drive.
Clone an existing Windows OS (Windows 7 or later) to a USB Drive as a Windows To Go Workspace.
Use of a Non-Enterprise Edition of Windows 10/8.1/8/7 to create Windows To Go Workspace.
Creation of Windows To Go on Non-Certified Windows To Go USB Drive.
Support for creating VHD-based/VHDX-based Windows To Go Workspace.
Support for creating Windows installation USB drives.

Important notes:
Windows 7/2008 R2 does not have built-in USB 3.0 support, so Windows 7/2008 R2 will have to be booted from a USB 2.0 port.
USB flash drives are very slow. It takes a long time to install and run Windows from a USB flash drive, highly recommend using a USB hard disk.
Windows To Go drives can be booted on different computers, so you can carry it to anywhere and use it on any computer.
Windows 7/2008 R2 is not completely portable. You may have activation and driver problems when booting on different computers.