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Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Out-of-band update
Out-of-band

KB5078127

KB5078127: Cumulative update for Windows 11, versions 24H2 and 25H2, January 2026. Cloud-file errors and Outlook hangs fixed

In short

Some apps and Outlook setups can open or save cloud files again after errors and hangs began with January updates. This out-of-band update adds that fix.

Does it affect you? Applies to: This update is for Windows 11, version 25H2 (OS build 26200.7628) and version 24H2 (OS build 26100.7628), on x64 and Arm64 devices.

Builds
26100.7628 · 26200.7628
Restart
Required
Review notes Additional details from the official release notes (1) Read note
  • Why do I have it? This cumulative update includes fixes and improvements from the January 13 and January 17 updates, as well as the additional cloud-file fix.

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

What changes

Improvements 2 changes

AI components

For: Copilot+ PC users

  • AI components are updated on Copilot+ PCs.1
    Image Search, Content Extraction, Semantic Analysis, and Settings Model are updated to version 1.2511.1224.0. These components apply only to Copilot+ PCs.

Servicing stack

  • The component that installs Windows updates receives quality improvements.2
    Includes servicing stack update KB5071142, build 26100.7295.

Fix 1 change

File System

  • Some apps and Outlook setups can open or save cloud files again after errors and hangs.3
    Fixes problems opening or saving files in cloud storage such as OneDrive or Dropbox after updates released on or after January 13, 2026. In some Outlook configurations, PST files stored on OneDrive could cause Outlook to hang or fail to reopen; sent items could be missing, or downloaded email could be downloaded again.

Known issues

  1. Open Affects: Organizations and IT administrators

    Password icon might be missing or invisible in the lock screen sign-in options

    The password icon might be missing from lock-screen sign-in options, mainly in enterprise or managed IT settings. Microsoft lists this issue as open for this update.4

    How to apply the workaround Workaround

    Select the blank space where the password icon should appear to open the password box, then enter the password. KB5074105 is named as addressing this issue.4

Technical details

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

Data sheet

Released
2026-01-24
Classification
Updates
Type
Cumulative update
Restart
Required
Replaces
KB5077744, KB5074109, KB5072033, KB5070311
+40 earlier KB5068861, KB5067036, KB5070773, KB5066835, KB5065789, KB5068221, KB5065426, KB5064081, KB5063878, KB5062660, KB5064489, KB5062553, KB5060829, KB5063060, KB5060842, KB5058499, KB5061977, KB5058411, KB5055627, KB5059087, KB5055523, KB5053656, KB5053598, KB5052093, KB5051987, KB5050094, KB5050009, KB5048667, KB5046740, KB5046617, KB5044384, KB5044284, KB5043178, KB5043080, KB5041865, KB5041571, KB5040529, KB5040435, KB5039304, KB5039239
Replaced by
KB5077181
VersionBuildChannel
24H2 26100.7628 General availability
25H2 26200.7628 General availability

Security

No vulnerabilities are listed for this update.

Updated components

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

Sources

Updated
Cited passages from Microsoft's official notes (4)
  1. 1. This release updates the following AI components: 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: After installing the Windows update released on and after January 13, 2026, some applications became unresponsive or encountered unexpected errors support.microsoft.com
  4. 4. Password icon might be missing or invisible in the lock screen sign-in options support.microsoft.com
Checked automatically: 8 of 8 checks passed, 4 quoted passages · compared with Microsoft's page on Oct 21, 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 5/5, 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