A common "broken" behavior of Windows 10 QCOW2 files is that they grow much larger than the actual data used. To fix this and reclaim space:
#!/bin/bash # Windows 10 Qcow2 Download Fixer Script set -e
qemu-img convert -c -O qcow2 Windows10_Fixed.qcow2 Windows10_Compacted.qcow2 Windows 10 Qcow2 Download Fixed
The cluster_size=2M flag prevents fragmentation on NVMe/SSD hosts, and preallocation=metadata stops the "growing file" lag that causes VM freezes.
sudo apt-get install qemu-utils -y # Debian/Ubuntu A common "broken" behavior of Windows 10 QCOW2
Qcow2 supports internal snapshots. This allows you to save the state of the VM within the disk file itself without creating massive external snapshot files. It makes rolling back changes instant and space-efficient.
The primary feature of qcow2 is "Copy-on-Write." In a traditional raw disk image, if you create a 50GB virtual disk, it consumes 50GB of physical space on your host drive immediately. With qcow2, the file starts small and grows only as data is written to it. This saves massive amounts of storage when deploying multiple virtual machines. This allows you to save the state of
There is no single "Microsoft official Windows 10 Qcow2" download. Microsoft provides VHDX and ISO files, not Qcow2. However, the workflow involves converting the official VHDX to Qcow2 and injecting the latest VirtIO drivers.
If you absolutely do not want to build your own, three repositories provide pre-verified, fixed images: