how to fix 2026-03 update (KB5085516) (26200.8039)

KB5085516 is an out-of-band cumulative update for Windows 11 versions 25H2 and 24H2 released on March 21, 2026 to fix an issue where some users cannot sign in to Microsoft apps and services with a Microsoft account after the March 2026 security update.

To install or fix issues with this update on a Windows 11 home device:

1. Use Windows Update
   • Open Settings → Windows Update.
   • Select Check for updates.
   • If the out-of-band update for KB5085516 is offered, allow it to download and install.
   • Restart the device when prompted.
2. Use Microsoft Update Catalog (if Windows Update fails)
   • Download KB5085516 for the correct Windows 11 version (25H2 or 24H2) from the Microsoft Update Catalog.
   • Run the downloaded package and follow the on-screen instructions.
   • Restart the device after installation.

After installation, the build should be updated to OS Build 26200.8039 or 26100.8039, and Microsoft account sign-in issues in apps should be resolved.

If problems persist after installing KB5085516 (for example, update fails repeatedly or sign-in issues continue), wait for the next cumulative update or contact Microsoft Support, as this update is specifically intended to correct the March 2026 sign-in issue.

References:

• Windows message center

KB5085516 is not a normal update, it is an out-of-band update Microsoft released to fix a problem some users were experiencing when they tried to log into apps like the Microsoft Office apps.

If you are not experiencing the problem logging into Office apps and if that update will not install correctly, the best option is to pause your updates until the April monthly update is released, that should then install correctly.

Hi Jafta,

Please try uninstalling the problem update following this article: How to uninstall a Windows Update.

If the update is not listed there, please perform an In-place upgrade.

Disclaimer: Let’s try performing an in-place install or in-place upgrade which will refresh your Windows files and operating system without removing files or applications. That being said, we always recommend that if you have important data, you should back it up before making large system changes. If you want to back up your data first, please do so. Once you are done backing up, you can follow the steps in the following guides: How to run In-place upgrade in Windows 11 - Microsoft Community

After that, your system will have 25H2 without recent updates, you may choose to pause Windows Update and wait for future patches.

I hope that above information is helpful to you.