Windows 7 was engineered during an era dominated by mechanical hard disk drives. Inside your virtual machine, disable background functions designed for spinning disks to minimize unnecessary host CPU cycles and QCOW2 ballooning:

After shutting down the VM, run the following command on your Linux host to shrink the QCOW2 file down to its actual used size:

To deploy your finished Windows 7 QCOW2 file into a Proxmox VE node, use the command-line tool to import the disk directly into an existing VM ID (e.g., VM 100): qm importdisk 100 windows7.qcow2 local-lvm Use code with caution. Security Best Practices for Legacy Windows 7 VMs

qemu-img convert -p -f raw -O qcow2 windows7.raw windows7.qcow2