This is a restriction imposed by Windows.

Important: Windows cannot boot from a USB connected drive. You can clone to a hard drive installed in your computer or to a hard drive installed in a USB hard-drive Caddy. Cloning your hard drive creates a bootable new hard drive with the state of your computer at the time you undertook the clone.

With Macrium Reflect you can boot the target disk on the same system after cloning. This is useful if you are upgrading to a larger hard drive. It is possible to clone an entire hard drive or specific partitions on a hard drive. But, we don’t need to do it manually we can use Macrium Reflect to migrate the entire Microsoft operating system (MOS) from the old PC to the new PC. We have apps, programs, files, and settings that we want to keep. We know that this job could be annoying, and losing information is not an option we want to consider. Everything goes perfectly until we want to have exactly the same data that was on the old PC. Even upgrading from an HDD to an SSD can bring a massive (and exciting) increase of performance for most PCs. Everyone knows how exciting it is to get a new computer and all the benefits this brings to our lives.

Macrium reflect backup windows