Using classic Outlook for Windows in business environments
Thank you for reaching out to the Microsoft Q&A Forum.
Based on your description, it appears you may be encountering a known issue affecting Classic Outlook for Windows that started after the January 13, 2026 Windows Update, specifically KB5074109.
Microsoft’s advisory is here: Classic Outlook POP account profiles hang and freeze after Windows 11 update to KB5074109
To better understand your situation, could you please confirm whether you are using a POP account and whether your device has installed Windows update KB5074109?
If you find that KB5074109 is installed, you may want to consider uninstalling it and then restarting your computer. Here are the steps:
-Open Settings and select Windows Update
-Choose Update history
-Scroll down and select Uninstall updates
-Locate KB5074109
-Click Uninstall, then restart your PC
Numerous cases have been reported, and several users have confirmed that uninstalling KB5074109 allowed Outlook to work normally again.
Note: Removing an update may reduce security posture temporarily, so if you’re in a managed environment, please coordinate with your IT administrator.
I hope this helps
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