The file only occupies the actual space used by the Windows installation, expanding as you add data.
Unlike raw disk images that pre-allocate the entire file size on your host storage, uses "thin provisioning". Windows 10.qcow2
You can create "linked clones" where a base Windows 10.qcow2 remains read-only while multiple VMs store their unique changes in smaller, separate overlay files. How to Create a Windows 10.qcow2 Image The file only occupies the actual space used
QCOW2 natively supports multiple snapshots, allowing you to save the VM's state and roll back instantly—perfect for testing Windows updates or software. Windows 10.qcow2