Classic Outlook profiles with POP accounts and PSTs hang after Windows updates on January 13, 2026

Last Updated: January 20, 2026

ISSUE

After Windows updates on January 13, 2026 users with Outlook POP account profiles and profiles with PST files report that Outlook hangs and does not exit properly. This issue may occur for any Outlook profile that has PSTs stored on OneDrive.

Symptoms reported include:

Outlook hangs and shows “Not Responding”.
Inability to reopen Outlook without ending its process in Task Manager or restarting the computer.
Emails not appearing in the Sent Items folder despite being sent.
Outlook redownloading emails.

Affected platforms:

Windows 11 25H2 KB5074109, Windows 11, version 25H2 update history.
Windows 11 24H2 KB5074109, Windows 11, version 24H2 update history.
Windows 10 22H2 KB5073724, Windows 10 update history.

STATUS: INVESTIGATING

The Windows Team will be documenting fix guidance. We will update this topic with a link to the Windows guidance as soon as it is available.

WORKAROUND

Until a fix is available, please use webmail. The other workarounds may be complicated. Please see the forum thread linked below for reference.

Use webmail.
Move PSTs out of OneDrive. For more information, please go to How to remove an Outlook .pst data file from OneDrive.
Remove the Windows Update. For more information, please go to How to uninstall a Windows Update.

This issue is being discussed in the Learn forums if you want to ask questions or share feedback here: