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Windows Server 2025 Windows Server 2025 Out-of-band update
Out-of-band

KB5061977

KB5061977: Cumulative update for Windows Server, version 2025, May 2025. Hyper-V guest hangs fixed; print and replication issues remain

In short

Confidential virtual machines on Hyper-V might stop responding or restart unexpectedly; this update fixes that problem. Print to PDF and Active Directory replication issues are also listed.

Does it affect you? Applies to: Devices running Windows Server 2025. The Hyper-V fix primarily affects Azure confidential virtual machines.

Build
26100.4066
Review notes Additional details from the official release notes (2) Read notes
  • This page The fix addresses a problem affecting confidential virtual machines on Hyper-V with Windows Server 2025, primarily Azure confidential VMs.
  • Known issues Duplicate schema entries on the Windows Server 2025 schema master can make schemas inconsistent and break replication across the entire Active Directory enterprise.

The official sources are linked at the end of the page.

Microsoft publishes separate notes for this KB for Windows 11.

What changes

Improvements 2 changes

Catalog

  • The x64 download name on the Catalog tab was corrected.1
    On June 1, 2026, Microsoft corrected the x64 .msu update string shown on the Catalog tab.

Servicing stack

For: Windows Server 2025 devices

  • The update includes quality improvements to the component that installs Windows updates.2
    Includes servicing stack update KB5058523, build 26100.4060.

Fix 1 change

Hyper-V Platform

For: Devices running confidential virtual machines on Hyper-V, primarily Azure confidential VMs

  • Confidential virtual machines on Hyper-V might stop responding or restart unexpectedly. This can affect service availability and require manual intervention.3
    Fixes an issue in the direct send path for a guest physical address (GPA). The issue primarily affects Azure confidential VMs.

Known issues

  1. Open Affects: Organizations and IT administrators

    Active Directory Replication

    Windows Server 2025 domain controllers holding the schema master role might allow duplicate schema entries, causing replication to fail. Microsoft lists it as open and names KB5068861 as the update that addresses it.4

    Workaround status No workaround yet

    Microsoft has not published a manual workaround for this issue yet. Monitor release health until a resolving update is available.

  2. Open Affects: Everyone

    Print to PDF might not work

    The Microsoft Print to PDF printer might disappear, and enabling its feature might fail with error 0x800f0922. This issue remains listed as open; Microsoft names KB5062553 as the update that addresses it.5

    Workaround status No workaround yet

    Microsoft has not published a manual workaround for this issue yet. Monitor release health until a resolving update is available.

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2025-05-27
Type
Cumulative update
VersionBuildChannel
2025 26100.4066 General availability

Security

No vulnerabilities are listed for this update.

Updated components

38 files changed since the previous update for the same versions.

Top changed componentsFiles
Hyper-V and virtualization10

Sources

Updated
Cited passages from Microsoft's official notes (5)
  1. 1. Corrected the x64 .msu update string on the Catalog tab for KB5061977 (this update) support.microsoft.com
  2. 2. This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. support.microsoft.com
  3. 3. Fixed: An issue in the direct send path for a guest physical address (GPA) where confidential virtual machines running on Hyper-V with Windows Server 2025 might intermittently stop responding or restart unexpectedly support.microsoft.com
  4. 4. This issue is addressed KB5068861. support.microsoft.com
  5. 5. This issue is addressed in KB5062553. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 5 quoted passages · compared with Microsoft's page on Nov 8, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 3/5, clarity 4/5, completeness 4/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake