Microsoft Releases Second Emergency Update, KB5078127, to Fix Windows 11's Cloud File & Outlook Issues

The first Patch Tuesday update for Windows 11 in 2026 turned out to be a disaster. After pushing an emergency update last week, Microsoft has now released a second emergency update to deal with problems introduced by January’s updates.

Second emergency Windows 11 update, KB5078127, out to fix cloud file issues

Yesterday, Microsoft rolled out KB5078127, an out-of-band update for Windows 11 versions 24H2 and 25H2, aimed at fixing file system issues tied to cloud storage services like OneDrive and Dropbox. The update is cumulative and builds on fixes included in KB5074109 and the earlier emergency patch KB5077744.

According to Microsoft, devices that installed updates released on or after January 13 began showing serious problems when opening or saving files stored in cloud-based locations. In some cases, affected apps became unresponsive or crashed unexpectedly, making everyday workflows unreliable.

Outlook users were hit hard

The issue was especially noticeable in certain Outlook configurations where PST files are stored on OneDrive. Microsoft confirmed that Outlook could hang indefinitely and fail to reopen unless users manually ended the process or restarted their system. Some users also reported missing Sent Items or Outlook re-downloading emails that were already present.

If this sounds familiar, KB5078127 is designed to address exactly those symptoms. The update is now available via Windows Update for systems that already installed KB5074109 or KB5077744, and it can also be downloaded manually from the Microsoft Update Catalog.

January 2026 Patch Tuesday fallout continues

The January patch, KB5074109, has reportedly also broken Sleep Mode on some PCs, while few other users are having issues with frequent app crashes and system lockups. Although the update does address a false security alert linked to the WinSqlite3.dll file, it has introduced new problems elsewhere.

Microsoft has warned that KB5074109 could lead to insecure Windows Deployment Services (WDS) deployments on Windows Server systems. At the same time, some PCs are failing to install the KB5074109 update altogether, throwing various error codes during installation.

Last but not least, NVIDIA users are reporting random black screens after installing the latest patch, while enterprise users say KB5074109 has disrupted Azure Virtual Desktop connections, leading Microsoft to issue an updated advisory.

For now, Microsoft says KB5078127 should stabilize file access and Outlook behavior tied to cloud storage. Whether this finally puts an end to Windows 11’s rough start to 2026 remains to be seen.