Last week, Microsoft released the first Patch Tuesday updates of 2026 on Windows 11 under KB5074109 and KB5073455. Alongside that, the company also published related dynamic updates under KB5074108, KB5074208, and KB5073454.
Unfortunately for users, the Patch Tuesday update has had two major issues and as such, Microsoft was forced to release emergency OOB updates for them to patch those issues under KB5077744 and KB5077797.
Microsoft has also confirmed problems on classic Outlook as many users claim that the new Windows 11 25H2 and 24H2 update, KB5074109, made the app "completely unusable" as there are random hangs and freezes, unsaved email progresses, and more.
On a thread tracking the issue, a user John W wrote: "Outlook classic is completely unusable since this forced windows update. Random hangs, not saving emails, etc. Hours of troubleshooting to no avail... Uninstalling the update KB5074109 fixed it for me! I am now able to close outlook gracefully, reopen it, and all of my progress is saved."
The response was upvoted by 28 users at the time of writing so clearly many people found it helpful. The thread was originally started by Chris Seagrave and they too note that uninstalling the update fixed the issue.
An IT business named Suncoast Information Systems also confirmed that multiple devices on their chain that were facing such issues, are no longer experiencing problems after uninstalling the latest Patch Tuesday.
If you are wondering about the specific issues users are having, Microsoft has documented it on a support article. The company explains: "After updating Windows 11 to KB5074109 January 13, 2026 users with Outlook POP account profiles report that Outlook is not exiting properly. This means that Outlook will not restart after you close it. In addition, some users report issues with Outlook hangs or freezes."
Microsoft says that there may be more symptoms that are yet to be understood and associated with this bug, and hence it is waiting for further investigation to confirm them. Interestingly, Microsoft has not released any workaround of its own so it looks like uninstalling Windows 11 KB5074109 is the only solution for now.
Update, Jan 21 2026, 20.00 GMT: Microsoft has finally issued workarounds.