virsh snapshot-create-as win10 clean-state "After Windows activation" virsh snapshot-revert win10 clean-state
qemu-img create -f qcow2 -o cluster_size=64K,preallocation=metadata windows10.qcow2 120G windows 10qcow2
You can create a "base" Windows 10 qcow2 image (fully activated and updated) and then create dozens of "overlay" images for individual users or tests. Each overlay is just a few MB initially and only stores differences. This is a game-changer for labs. Create a base image (golden master) and never
Create a base image (golden master) and never modify it: The boot sector (MBR or GPT) was not preserved correctly
Unlike the rigid, pre-allocated VHDX (Hyper-V) or VMDK (VMware) formats, the qcow2 format offers dynamic allocation, snapshotting, and compression. But finding or creating a ready-to-use Windows 10 qcow2 image is not as straightforward as downloading an ISO. This article will walk you through everything you need to know: what a qcow2 file is, how to obtain a Windows 10 qcow2 image, how to create one from scratch, and advanced optimization techniques.
The boot sector (MBR or GPT) was not preserved correctly. Solution: Use qemu-img convert with no additional flags. If the issue persists, boot a Windows recovery ISO and run bootrec /fixmbr and bootrec /rebuildbcd .