April 14, 2026—KB5082123 (OS Build 17763.8644)

[PowerShell (known issue)] Fixed: After installing Windows updates released on or after January 13, 2026, Japanese language installations of Windows Server 2019 might not correctly display Japanese characters in the PowerShell console.

[Remote Desktop] This update improves protection against phishing attacks that use Remote Desktop (.rdp) files. When you open an .rdp file, Remote Desktop shows all requested connection settings before it connects, with each setting turned off by default. A one-time security warning also appears the first time you open an .rdp file on a device. For more information, see Understanding security warnings when opening Remote Desktop (RDP) files.

[Vulnerable driver blocklist] This update introduces a security hardening change that adds known vulnerable kernel drivers to the Microsoft vulnerable driver blocklist. Backup applications that rely on blocked drivers might experience failures when attempting to mount or manage disk images.
These apps relying on blocked drivers might display error messages, including "The backup has failed because Microsoft VSS has timed out during the snapshot creation" or VSS_E_BAD_STATE. Affected users should update to a newer version of their application that uses newer drivers that include the required protections. For more information, see April 2026 Windows security updates introduce protections to known vulnerable kernel drivers.

[Windows Deployment Services (WDS)] This update disables the “Hands-Free Deployment” feature in WDS by default and is no longer a supported feature. For more information about this change, see Windows Deployment Services (WDS) Hands-Free Deployment Hardening Guidance related to CVE-2026-0386.

[Kerberos protocol] This update changes the default DefaultDomainSupportedEncTypes value for Kerberos Key Distribution Center (KDC) operations to leverage AES-SHA1 for accounts that do not have an explicit msds-SupportedEncryptionTypes Active Directory attribute defined. For more information see, How to manage Kerberos KDC usage of RC4 for service account ticket issuance changes related to CVE-2026-20833.

[Secure Boot]

• This update enables dynamic status reporting for Secure Boot states in the Windows Security App (Settings > Update & Security > Windows Security). Learn more about the status alerts via badges and notifications. Note that these enhancements are disabled by default on commercial devices and servers.
• This update fixes an issue that could cause a device to enter BitLocker Recovery after Secure Boot updates.
• With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Devices receive the new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.

Domain controllers might restart repeatedly after installing this update

Symptoms

After installing this update, domain controllers in environments with multiple domains in the forest that use Privileged Access Management (PAM), might experience LSASS crashes during startup. As a result, affected domain controllers might restart repeatedly, preventing authentication and directory services from functioning, and potentially rendering the domain unavailable.

Resolution

This issue is addressed in out-of-band update KB5091573.

Remote Desktop security warnings might not display correctly

Symptoms
After installing this update, the security warning that appears when opening Remote Desktop (RDP) files might not display correctly in some cases.
This issue might occur when you use more than one monitor with different display scaling settings (for example, one display set to 100% and another set to 125%). When this happens, the warning window might show overlapping text or partially hidden buttons, which can make the message difficult to read or interact with.
Resolution

This issue is resolved in Windows updates released on and after May 12, 2026 (such as KB5087538). We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.

[Remote Desktop] This update improves protection against phishing attacks that use Remote Desktop (.rdp) files. When you open an .rdp file, Remote Desktop shows all requested connection settings before it connects, with each setting turned off by default. A one-time security warning also appears the first time you open an .rdp file on a device. For more information, see Understanding security warnings when opening Remote Desktop (RDP) files.

[Secure Boot]

• This update enables dynamic status reporting for Secure Boot states in the Windows Security App (Settings > Update & Security > Windows Security). Learn more about the status alerts via badges and notifications. Note that these enhancements are disabled by default on commercial devices and servers.
• This update fixes an issue that could cause a device to enter BitLocker Recovery after Secure Boot updates.
• With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Devices receive the new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.

[Vulnerable driver blocklist] This update introduces a security hardening change that adds known vulnerable kernel drivers to the Microsoft vulnerable driver blocklist. Backup applications that rely on blocked drivers might experience failures when attempting to mount or manage disk images.
These apps relying on blocked drivers might display error messages, including "The backup has failed because Microsoft VSS has timed out during the snapshot creation" or VSS_E_BAD_STATE. Affected users should update to a newer version of their application that uses newer drivers that include the required protections. For more information, see April 2026 Windows security updates introduce protections to known vulnerable kernel drivers.

Remote Desktop security warnings might not display correctly

Symptoms
After installing this update, the security warning that appears when opening Remote Desktop (RDP) files might not display correctly in some cases.
This issue might occur when you use more than one monitor with different display scaling settings (for example, one display set to 100% and another set to 125%). When this happens, the warning window might show overlapping text or partially hidden buttons, which can make the message difficult to read or interact with.
Resolution

This issue is resolved in Windows updates released on and after May 12, 2026 (such as KB5087538). We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.