Imagine you want 5 Windows 11 VMs for testing. Instead of 5 x 80GB = 400GB, use a backing file.

If you are using VirtualBox or VMware, stick to VDI/VMDK. But for , QCOW2 is non-negotiable.

Many pre-made QCOW2s already have these requirements bypassed.

The best Windows 11 QCOW2 installation balances performance, trust, and convenience. For 99% of users, generating your own image via the remains the gold standard. However, if you need a disposable test environment, validated cloud images are acceptable.