Microsoft issued another out-of-band update to fix a bug that caused Outlook to crash for Windows 11 users. This second emergency patch addresses issues seen with Outlook and files stored in the cloud following Microsoft's January 2026 Windows security update.

Microsoft releases an urgent Windows 11 update to fix Outlook crashes caused by the January 2026 security patch and cloud file conflicts.

The out-of-band patch targets cloud file issues triggered by January’s security update, after Outlook users reported widespread crashes and freezes.

There are workarounds, though.

If your Outlook Classic freezes or hangs when you use POP accounts or deal with PST files, you'll need to remove Windows 11 KB5074109.

Microsoft has released emergency, out-of-band updates on Saturday for Windows 10, Windows 11, and Windows Server to fix an issue that prevented Microsoft Outlook classic from opening when using PSTs stored in cloud storage.

Microsoft shares workarounds for a Windows 11 KB5074109 bug that breaks Outlook for POP email accounts and PST files.