What is the best free disk imaging software for windows os backup?

A disk imaging software creates an exact, sector-by-sector snapshot of your entire hard drive or specific partitions, saving it as a single compressed file (an "image"). Unlike standard file backup, which copies only individual files and folders, a disk image preserves everything, including boot sectors, operating system settings, installed apps, hidden files, and even deleted data remnants.

This makes it invaluable for disaster recovery: if your drive fails or Windows 11 becomes corrupted, you can restore the full system to a new drive exactly as it was, without reinstalling or reconfiguring anything.

To choose the best disk imaging software for Windows 11, prioritize three factors: bootable recovery media (essential for restoring when Windows won't start), incremental/differential backups (saves time and space by only capturing changes), and native Windows 11 compatibility (including support for BitLocker, ReFS, and modern NVMe drives).

Also check for features like compression level, encryption, and the ability to restore to different hardware (useful for upgrades).