Windows 7 retains driver references from the old hypervisor. Boot the new Qcow2 image via QEMU, press F8 before Windows loads, select "Safe Mode." Once in Safe Mode, run sysprep with the "Generalize" option (from C:\Windows\System32\sysprep\sysprep.exe ). This strips old HAL and storage drivers, forcing Windows 7 to rediscover the VirtIO environment.
The standout feature here is the native support for copy-on-write snapshots . Being able to "roll back" the OS after testing legacy software or handling a malware sample is seamless and takes seconds.
Elena realized she had to build it herself. She had her old, space-hogging 50GB Win7_Raw.img file. She decided to perform a conversion. This is the most useful aspect of the Qcow2 format: it allows for compression and snapshot integration.
During Windows 7 setup, when the installer asks "Where do you want to install Windows?" you will see no disks. Click "Load Driver" and browse the VirtIO ISO → amd64 → w7 → viostor.inf .