Problem: WIndows Computer Shuts down during extraction process
Likely Cause: OVRServiceLauncher.exe
Proposed Solution: Uninstall oculus software
During extraction windows users may experience an unexpected shutdown and automatic reboot in the process of the extraction immediately preceding the creation of the alignments.fsa file.
The cause seems to be the OVRServiceLauncher process which is a component of the oculus software needed to run oculus home and the VR headset.
To verify this is (probably) the culprit on your own system, after your system reboots, use the event viewer and look under " windows logs > applications " for the error for the service around the same time as your system shutdown.
I don't know how to prove beyond a shadow of a doubt this is the culprit but I have uninstalled the software and haven't had a problem since.