KB5087538: [Remote Desktop security warnings (known issue)] Fixed

May 12, 2026—KB5087538 (OS Build 17763.8755)

Applies to: Windows Server 2019

This security update includes fixes and quality improvements that are part of the following update:

• April 14, 2026—KB5082123 (OS Build 17763.8644)
• April 19, 2026—KB5091573 (OS Build 17763.8647) Out-of-band

The following is a summary of the issues that this update addresses when you install this update. The bold text within the brackets indicates the item or area of the change we are documenting.

• [Remote Desktop security warnings (known issue)] Fixed: The Remote Desktop Connection security warning dialog might render incorrectly in multi-monitor configurations with different display scaling settings. This issue might occur after installing the Windows security update released on or after April 14, 2026 (such as KB5082123).

[Secure Boot]

• This update enables dynamic status reporting for Secure Boot states in Windows Security App.
• 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.
• [Sign-In] Fixed: After you install the Windows update released on or after March 10, 2026, some users might experience an issue signing in to apps with a Microsoft account. Even when the device has a working Internet connection, a “no Internet” error appears during sign in and prevents access to Microsoft services and apps such as Microsoft Teams.
• [Daylight Savings Time] Update for Arab Republic of Egypt to support the government DST change order in 2023.

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