January 18, 2018—KB4075200 (OS Build 10586.1358)

Improvements and fixes

This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

Addresses issue where some customers on a small subset of older AMD processors get into an unbootable state.
Addresses issue where a part of the system does not log off correctly, which leads to repeated queries for user credentials.
Addresses issue originally called out in KB4056888 where calling CoInitializeSecurity with the authentication parameter set to RPC_C_AUTHN_LEVEL_NONE resulted in the error STATUS_BAD_IMPERSONATION_LEVEL.
Addresses issue where users of Microsoft and Azure Active Directory accounts may see the password prompt repeatedly.

If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

For more information about the resolved security vulnerabilities, see the Security Update Guide.

Windows Update Client Improvement

Microsoft will release an update directly to the Windows Update Client to improve Windows Update reliability. It will only be offered to devices that haven't installed the most recent updates.

Known issues in this update

Symptom	Workaround
After installing this update, some users may experience issues logging into some websites when using third-party account credentials in Microsoft Edge.	This issue is resolved in KB4074591.