Last month I reported how the April Windows 10 "Patch Tuesday" updates were freezing some computers
during the update process itself and preventing others from rebooting afterwards. Now it appears that the latest operating system updates are once again preventing Windows 10 computers from rebooting properly. The previous issue only involved users running certain antivirus solutions, but this time it's anyone. Or at least anyone who wants to restore their computer back to a point before the latest Windows 10 update was installed. Which is, let's face it, a pretty common scenario considering the problematical nature of the update process. Bleeping Computer was first to spot
that Microsoft had updated a support document regarding system restore reboot problems. As long as you have system protection turned on in Windows 10 and have created a system restore point before applying the latest update, then you are at risk of being frozen out of your computer. Simple as. Microsoft confirms
that under those circumstances the computer may experience "a Stop error (0xc000021a)" and when you restart the device "the system cannot return to the Windows desktop." In other words, your computer is borked in a failed reboot scenario caused by the Windows 10 update that is meant to protect your system from potential harm.
How do you fix it? Restart the computer and enter the Windows Recovery Environment (WinRE) which should happen automatically after two consecutive failed attempts to start Windows 10. From the WinRE screen, select "Troubleshoot|Advanced options|More recovery options|Startup settings" and then the "Restart now" option. A number of startup settings will be available and you need to ensure you have selected "Disable driver signature enforcement." Microsoft advises that the F7 key may need to be employed in order to select this setting. The startup process will now proceed and system restore should resume and complete as intended.