Security update for Windows 10, version 1507, Windows 8.1, Server 2012 R2, and Server 2012: February 11, 2020

Applies to: Windows 10Windows 8.1Windows Server 2012 R2


This update makes improvements to the supported Windows OS versions listed in the "Applies to" section. Key changes include the following:

  • Addresses an issue in which a third-party Unified Extensible Firmware Interface (UEFI) boot manager might expose UEFI-enabled computers to a security vulnerability.

To learn more about this security update, see Microsoft Common Vulnerabilities and Exposures.

Known Issues

Symptom Workaround

You might encounter issues trying to install or after installing KB4502496.

This issue was resolved in KB4535680. This update should only be offered if it is applicable to your device. You might need to update UEFI firmware of your devices or adjust other settings before deploying this update. For more information, see KB4535680.

If KB4502496 is installed and you are experiencing issues, you can uninstall this update.

  1. Select the start button or Windows Desktop Search and type update history and select View your Update history.
  2. On the Settings/View update history dialog window, Select Uninstall Updates.
  3. On the Installed Updates dialog window, find and select KB4502496 and select the Uninstall button.
  4. Restart your device.


How to get this update

Important This standalone security update has been removed due to an issue affecting a sub-set of devices. It will not be re-offered from Windows Update, Windows Server Update Services (WSUS) or Microsoft Update Catalog. Note Removal of this standalone security update does not affect successful installation or any changes within any other February 11, 2020 security updates, including Latest Cumulative Update (LCU), Monthly Rollup or Security Only update. 


There are no prerequisites to apply this update.

Restart information 

Your device does not have to restart when you apply this update. If you have Windows Defender Credential Guard (Virtual Secure Mode) enabled, your device will restart two times. 

Update replacement information 

This update does not replace any previously released update.

File information

File verification

File attributes

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.

Windows 10

Windows 8.1 and Windows Server 2012 R2

Note The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.

Windows Server 2012

Note The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.


Learn about the terminology that Microsoft uses to describe software updates.