Microsoft has urgently rolled out updates for Windows 10, Windows 11, and Windows Server to address a critical issue affecting Microsoft Outlook classic. The problem was causing the application to freeze when attempting to open PST files stored in cloud services like OneDrive and Dropbox.

Since the January 2026 Patch Tuesday updates, users of the Outlook app have been facing difficulties as the application freezes upon launch if a PST file is stored in cloud storage. PST files are essential data files used by Outlook to save a user’s emails and other data locally on their device instead of on the mail server. These files are commonly used in enterprise settings to access emails offline and back up important messages.

According to Microsoft, applications might become unresponsive or encounter unexpected errors when handling files from or saving files to cloud-backed storage. Specifically, Outlook users storing PST files on OneDrive may experience unresponsiveness and failure to reopen unless the process is terminated in Task Manager or the system is restarted.

Microsoft has released out-of-band updates to address the Outlook freezing issue. Affected users can install the updates through Windows Update or the Microsoft Download Catalog.

Microsoft’s OOB Updates

The recent updates also address bugs related to Microsoft 365 Cloud PC sessions and PCs with Secure Launch enabled facing shutdown or hibernation issues. Previously, manual installation was required for OOB updates, but now these fixes are included in the latest updates.

If the mentioned issues do not impact your devices, there is no immediate need to install the out-of-band updates. Alternatively, users can wait for upcoming preview updates or the next Patch Tuesday release for the fixes to be included in the regular update cycle.

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