qemu-img convert -f vmdk -O qcow2 windows7.vmdk win7.qcow2
Windows 7 supports Unmap (equivalent to TRIM) only with specific storport drivers. To enable sparse reclamation on QCOW2: windows 7 qcow2 file
qemu-img create -f qcow2 -o encrypt.format=luks,encrypt.key-secret=sec0 windows7_encrypted.qcow2 50G qemu-img convert -f vmdk -O qcow2 windows7