Well, that ends my participation in Windows Insider. I will never install another Windows update unless it's been vetted and is -3. How does Microsoft defend a release like this that disables your computer? Is there NO quality control? Totally unacceptable.
Please, read the Windows Insider Program Agreement.
"IMPORTANT NOTICE:
The experimental and early prerelease software and services might not be tested.
You might experience crashes, security vulnerabilities, data loss, or damage to your device."