Microsoft released emergency out-of-band updates for Windows 10, Windows 11, and Windows Server to fix an issue that prevented classic Outlook from opening when PST files were stored in cloud-backed storage. The problem appeared after the January 2026 Patch Tuesday updates and affected PSTs on services like OneDrive and Dropbox, prompting KB updates and download links for affected OS versions. #Microsoft #Outlook
Keypoints
- Microsoft issued out-of-band updates to address Outlook classic failing to open PSTs stored in cloud-backed storage.
- The issue began after the January 13, 2026 Patch Tuesday updates and caused Outlook to become unresponsive when accessing PSTs on OneDrive or Dropbox.
- Affected behaviors included Outlook freezing, failing to reopen without termination or reboot, missing Sent Items, and duplicate downloads of previously retrieved email.
- Microsoft published specific KB updates for Windows 11, Windows 10, and multiple Windows Server versions and provided download links via Windows Update and the Microsoft Download Catalog.
- Admins who are not affected can wait for the preview update or next Patch Tuesday, while previous OOB fixes for Cloud PC and Secure Launch are included in these updates.