The qcow2 (QEMU Copy-On-Write) format is ideal because it starts small and grows as you install the OS, rather than allocating the full space immediately.

Ensure that after the first reboot, your boot order prioritizes the QCOW2 drive rather than looping back into the installation ISO. Step 5: Post-Installation Optimization and Tweaks

instead of SATA; Longhorn builds from this era typically do not support SATA drivers out of the box.

qemu-system-x86_64 \ -accel kvm -cpu host -m 2048 \ -cdrom longhorn.iso \ -drive file=windows-longhorn.qcow2,format=qcow2 \ -vga std -usb -device usb-tablet \ -rtc base=localtime

To make Longhorn work, you must actively "downgrade" the virtualized hardware environment. Modern QEMU defaults will crash the installer.

Longhorn was one of the first operating systems to drop the traditional blue-screen text mode setup in favor of a graphical WinPE environment.

Once the installer boots, follow the on-screen prompts. If you are installing an early milestone build, you may encounter the legendary "blue screen" text mode phase of setup combined with an early WinPE graphical environment.

Before installing, you need a virtual hard disk in qcow2 format. qemu-img create -f qcow2 longhorn.qcow2 20G Use code with caution.

You might be stuck with limited color depth. Use -vga cirrus to ensure at least basic accelerated graphics.

One of the most frustrating aspects of Longhorn QCOW2 work is getting the graphical effects to function. Out of the box, Longhorn will render in a basic VGA mode.

Windows Longhorn is generally divided into three eras. Your mileage and configuration will vary depending on the build: