Do not download random qcow2 files from torrent sites or file lockers. They often contain malware, backdoors, or corrupted partitions. Instead, use trusted sources:
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 windows 10qcow2
Enable the discard mount option to allow the guest OS to tell the QCOW2 file to shrink when files are deleted inside Windows. Converting ISO or VMDK to QCOW2 Do not download random qcow2 files from torrent
Understanding Windows 10 QCOW2: The Complete Guide to Virtualization Performance or corrupted partitions. Instead