Windows 10qcow2

You forgot VirtIO drivers. Check Device Manager → Storage controllers. If you see "Standard SATA AHCI Controller", you are not using VirtIO. Reinstall virtio-win-guest-tools .

Appendices (optional)

Understanding Windows 10 QCOW2: The Complete Guide to Virtualization Performance windows 10qcow2

Need to convert a raw disk or VDI to qcow2? It’s one line: qemu-img convert -f raw -O qcow2 windows10.img windows10.qcow2 You forgot VirtIO drivers