qemu-img convert -f vhdx -O qcow2 windows10.vhdx windows10.qcow2
Using virt-install (command line):
qemu-img create -f qcow2 -b windows10-base.qcow2 -F qcow2 win10-overlay1.qcow2 Run the VM using win10-overlay1.qcow2 . Any writes go to the overlay; the base remains pristine. To reset, simply delete the overlay and create a new one. Qcow2 files can become corrupt if the host crashes. Check integrity: windows 10qcow2