Microsoft seems to have messed up again with its latest Windows 11 update, which borks the classic Outlook app. Earlier this month, classic Outlook struggled to open encrypted emails. Now, Neowin reports that several users are saying the latest Windows 11 update (KB5074109) has made classic Outlook completely unusable.

Microsoft shared a temporary workaround for customers experiencing Outlook freezes after installing this month's Windows security updates.

Windows 11 Patch Tuesday updates for 24H2 and 25H2 reportedly break classic Outlook, causing freezes, hangs, and lost email drafts.

Microsoft is investigating a Windows 11 regression that is causing classic Outlook to hang, lag, or become unresponsive after the January 13, 2026 cumulative update (KB5074109).

While millions await permanent resolution from Microsoft, Stellar Repair for Outlook is helping hundreds of users remedy the situation by offering an immediate and proven solution. This powerful yet remarkably easy-to-use DIY tool quickly repairs and restores corrupted or inaccessible PST files.

Windows 11 KB5074109 causes Outlook freezing for POP accounts. Microsoft confirms the issue and investigates a permanent fix.

Microsoft has confirmed that the Windows 11 January 2026 Update is causing at least three major issues, rolling out fixes for two bugs.