Microsoft Shares Workarounds After KB5074109 Severely Broke Outlook on Windows 11

The first Patch Tuesday update for Windows 11 in 2026 has caused absolute havoc, with users complaining about multiple issues. In fact, the company had to push out emergency updates to fix some of the problems.

Microsoft shares workarounds for broken Outlook for POP email accounts after installing Windows 11 KB5074109

Last Friday, several users also reported that KB5074109 breaks Outlook, especially for POP email accounts, an issue Microsoft has since confirmed. In more severe cases, the update has triggered reboot loops, forcing affected users to rely on temporary workarounds shared online.

However, if you are among those affected by issues related to Classic Outlook profiles with POP accounts and PST files after installing the KB5074109 update, there is now a workaround shared by Microsoft.

In an official document spotted by folks at Neowin, Microsoft mentioned that until a permanent fix is available, it’s best to use webmail. Microsoft also mentions that other workarounds may be complicated. The other two options given by Microsoft are moving PSTs out of OneDrive and uninstalling the problematic KB5074109 update.

If you’ve been affected by the aforementioned issues, you may have noticed one of the following symptoms:

• 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.

As mentioned earlier, Microsoft doesn’t seem to have a permanent solution for this issue yet. However, the company confirmed that it’s looking into the problem. Hopefully, this will get fixed soon.

The issues are sadly piling up

The update, KB5074109, has reportedly also broken Sleep Mode on some PCs, while others are dealing with frequent app crashes and system lockups. Although the update does address a false security alert linked to the WinSqlite3.dll file, it has introduced new problems elsewhere.

Microsoft has warned that KB5074109 could lead to insecure Windows Deployment Services (WDS) deployments on Windows Server systems. At the same time, some PCs are failing to install the KB5074109 update altogether, throwing various error codes during installation.

Last but not least, NVIDIA users are reporting random black screens after installing the latest patch, while enterprise users say KB5074109 has disrupted Azure Virtual Desktop connections, leading Microsoft to issue an updated advisory.