# Inside Windows 7: Run Defragment and Optimize Drives, then use SDelete to zero free space sdelete -z c: qemu-img convert -O qcow2 -c windows7.qcow2 windows7_compressed.qcow2
-drive file=windows7.qcow2,format=qcow2,if=virtio,discard=unmap This allows the guest OS to tell the host which blocks are free, shrinking the QCOW2 file automatically. Over time, even after deleting files, the QCOW2 file may stay large. To shrink it: windows 7 qcow2 file
qemu-img create -f qcow2 -o encrypt.format=luks,encrypt.key-secret=sec0 windows7_encrypted.qcow2 50G You need to pass a secret via --object secret,... when launching QEMU. If you are dual-booting Linux, you can boot your Windows 7 QCOW2 file using qemu-nbd : # Inside Windows 7: Run Defragment and Optimize
Introduction: Why a Windows 7 QCOW2 File Still Matters In the rapidly evolving world of operating systems, Windows 7 remains a cornerstone for legacy applications, industrial control systems, and classic gaming. While Microsoft ended mainstream support, millions of users and enterprises still rely on Windows 7 for specific tasks. However, running it on bare metal today is a security risk. The solution? Virtualization. when launching QEMU