The lock screen is black or blank and does not respond to keyboard or swipe actions in Windows 10 Technical Preview


Symptoms


After you install the Windows 10 Technical Preview build 9879, a black or blank lock screen prevents you from logging on to Windows. When this problem occurs, the computer does not respond to keyboard or swipe actions.

Cause


This problem occurs because of a change in the behavior of WinLogon and LogonUI. This change introduces the potential for the deadlock.

Resolution


An update is available to resolve this problem.

How to obtain and install this update

Windows Update

Use Windows Update to automatically download and install the update.

Prerequisites

To apply this update, you must have Windows 10 Technical Preview build 9879 installed.

Registry information

To apply this update, you do not have to make any changes to the registry.

Restart requirements

You must restart your computer after you install this update.

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.