Microsoft releases emergency update to fix Outlook crash bug
26 Jan 2026

Microsoft has issued an emergency update (KB5078127) for Windows 11, following a critical bug that caused Outlook and other apps to crash.

The issue was particularly prevalent when trying to open or save files from cloud services like OneDrive.

The problem mainly affected users of the Classic version of Outlook with PST files stored on OneDrive.

Outlook users faced multiple issues post-January update
User impact

After the January 2026 update, Outlook Classic users with PST files on OneDrive experienced several problems.

These included the app freezing on startup, missing Sent Items, and requiring frequent restarts.

The issues were mainly linked to the recent security patch released by Microsoft for Windows 11.

New patch addresses previous bugs and crashes
Fix

The latest update from Microsoft not only fixes the Outlook crashes but also addresses Remote Desktop and shutdown bugs from earlier updates.

This makes it particularly important for users who rely on PST in Outlook.

If your apps have been misbehaving lately, it's recommended to install this update as soon as possible to restore normalcy without having to uninstall anything else.