Microsoft's January Windows Update Freezes Outlook When Saving to OneDrive

Microsoft's January 2026 Windows update has introduced a significant bug that causes applications, including Outlook, to freeze when saving files to cloud storage services like OneDrive or Dropbox. The issue, acknowledged by Microsoft days after releasing an emergency out-of-band update for other problems, affects users who have Personal Storage Table (PST) files stored on OneDrive, leading to unresponsive applications and failed email synchronization.

The Core Problem

After installing the January 13, 2026 update, some applications become unresponsive or experience errors when opening or saving files to cloud-backed storage. The issue is particularly severe for Outlook users with PST files on OneDrive. Microsoft's documentation states that Outlook "might become unresponsive and fail to reopen unless its process is terminated in Task Manager, or the system is restarted." Additionally, sent emails may fail to appear in the mailbox.

The problem stems from how the update handles file operations with cloud storage providers. When Outlook attempts to save changes to a PST file stored on OneDrive, the application encounters a conflict that causes it to hang. This is not the first issue with this update—Microsoft had already released an emergency out-of-band update to address connection and authentication failures in the Windows App, and another fault caused some Windows 11 23H2 PCs to refuse to shut down or hibernate.

Impact on Users and Workflows

The freezing issue disrupts common workflows, especially for users who store PST files on OneDrive for backup or synchronization purposes. While Microsoft generally recommends against storing PST files in OneDrive except for backup, many users and administrators do so for convenience or organizational policies. The bug forces these users to change their established workflows due to a problem introduced by a routine security update.

Microsoft's initial workaround is straightforward but inconvenient: move the PST file out of OneDrive. This recommendation appears in the company's Release Health dashboard, which tracks known issues with Windows updates. However, moving files can be disruptive, especially for users with large PST files or those relying on OneDrive for cross-device access.

Microsoft's Response and Workarounds

Microsoft has acknowledged the issue and is working on a resolution, but the company's immediate advice has drawn criticism. The official guidance suggests that users "contact the application developer for possible alternative methods of accessing the files." For Outlook specifically, Microsoft recommends using webmail "if supported by your email provider" as an alternative while the issue persists.

This response highlights the complexity of the problem, which involves interactions between Windows, Outlook, and third-party cloud storage services. Microsoft's statement that they are "working on releasing a resolution for this issue as soon as possible" indicates that a patch is in development, but no timeline has been provided.

Broader Context of Update Issues

This latest bug adds to a series of problems with Microsoft's January 2026 updates. Earlier in the month, Microsoft had to release an emergency out-of-band update to fix authentication failures in the Windows App. Additionally, the same update caused some Windows 11 23H2 systems to fail to shut down or hibernate properly. These cumulative issues have raised concerns about the quality control of Microsoft's update process, particularly for security updates that are typically deployed automatically.

The pattern of problems suggests potential issues with the testing procedures for updates that affect multiple components of the Windows ecosystem. While Microsoft has a robust system for tracking and addressing known issues through its Release Health dashboard, the frequency of problems with this month's updates is notable.

Recommendations for Affected Users

For users experiencing the Outlook freezing issue, the immediate steps are:

1. Move PST files from OneDrive: Transfer PST files to a local drive or a different cloud service that doesn't exhibit the same behavior.
2. Use webmail access: If your email provider supports webmail, access your email through a browser as a temporary workaround.
3. Monitor Microsoft's Release Health dashboard: Check for updates on the status of the fix at Microsoft's official support page.
4. Consider delaying updates: For organizations, this may reinforce the practice of testing updates in a controlled environment before broad deployment.

Looking Ahead

Microsoft's development of a fix will likely involve coordination between the Windows, Outlook, and OneDrive teams, given the cross-product nature of the issue. Once released, the update should restore normal functionality for PST files on OneDrive, but users should be prepared for potential data synchronization issues during the transition.

This incident underscores the challenges of maintaining compatibility across a complex software ecosystem, especially when cloud storage integration is involved. As more users rely on cloud services for critical data, the impact of such bugs grows, making rapid resolution essential for maintaining user trust in platform updates.

For the latest information on this issue and Microsoft's progress toward a fix, users should monitor the Windows Release Health dashboard and the Microsoft Support blog.