Think of it as a "Portable Macrium Reflect Operating System." You boot the target PC from a USB drive (or CD/DVD), and you have access to:
If you have a Technician's License, follow these steps to create your portable media: i--- Macrium Reflect Portable
The portable USB typically functions as both a bootable rescue environment (to fix PCs that won't start) and a portable Windows application (to create images while Windows is running). Think of it as a "Portable Macrium Reflect Operating System