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Windows 10 1809 Windows 10 1809 Out-of-band update
Out-of-band

KB5078131

KB5078131: Cumulative update for Windows 10, version 1809, January 2026. Cloud-file errors and Outlook hangs fixed

In short

Fixes file access errors in cloud storage and hangs in some Outlook setups that store PST files on OneDrive. A restart is required.

Does it affect you? Applies to: Devices running Windows 10 Enterprise LTSC 2019, version 1809.

Build
17763.8281
Restart
Required

Microsoft publishes separate notes for this KB for Windows Server.

What changes

Fix 1 change

File System

For: People using cloud-based storage, including OneDrive or Dropbox

  • Some applications can open and save files in cloud storage again. In certain Outlook setups, email no longer hangs or goes missing because of this issue.1
    Addresses an issue that began after Windows updates released on and after January 13, 2026. In certain configurations where PST files are stored on OneDrive, Outlook could hang and fail to reopen unless its process was terminated or the system restarted; sent items could be missing and previously downloaded emails could be downloaded again.

Improvement 1 change

Servicing stack

  • The component that installs Windows updates receives quality improvements.2
    The update includes servicing stack update KB5074222, build 17763.8260, combined with the latest cumulative update.

Known issues

  1. Resolved Affects: Everyone Resolved by KB5075904

    Some devices with Virtual Secure Mode enabled might fail to shut down or hibernate

    Some Secure Launch-capable PCs with Virtual Secure Mode enabled might restart instead of shutting down or entering hibernation after installing this update. KB5075904 addresses the issue.3

    Resolution Fixed in KB5075904

    Install KB5075904 (or a later cumulative update) on affected devices. No manual workaround is required after updating.

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
KB5077795, KB5073723, KB5074975, KB5071544
+13 earlier KB5068791, KB5066586, KB5065428, KB5066187, KB5063877, KB5062557, KB5060531, KB5061978, KB5058392, KB5059091, KB5058922, KB5050008, KB5037425
Replaced by
KB5075904
VersionBuildChannel
1809 17763.8281 General availability

Security

No vulnerabilities are listed for this update.

Updated components

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

Sources

Updated
Cited passages from Microsoft's official notes (3)
  1. 1. Fixed: After installing the Windows update released on and after January 13, 2026, some applications became unresponsive or encountered unexpected errors when opening files from or saving files to cloud-based storage, such as OneDrive or Dropbox. 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. This issue is addressed in KB5075904. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 3 quoted passages · compared with Microsoft's page on Sep 25, 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 5/5. 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