Outlook sometimes not responding since recent update

Question

Outlook sometimes not responding since recent Windows update. Sent emails not showing in "sent". Emails not deleting. Since update, each time Outlook is opened all emails come through as new emails including recently deleted emails, as though Outlook doesn't recognize that it has been opened for days.

Answer 1

Dear Peter Thomson,

Thank you for posting to the Microsoft Q&A and describing these symptoms so clearly.

I understand how disruptive it is when Outlook stops responding and your inbox becomes cluttered with previously deleted emails. The behavior you described—where Outlook "forgets" what you have read or deleted—is likely related to a known issue in the recent Windows Update (KB5074109).

You can track the official status of the fix in this support article: Classic Outlook POP account profiles hang and freeze after Windows 11 update to KB5074109

In the meantime, the best way to restore your workflow is to temporarily remove this specific update. Here are the steps to do that:

1. Open Windows Settings.
2. Go to Windows Update > Update History.
3. Scroll down to the "Related settings" section and click Uninstall updates.
4. Locate Security Update for Microsoft Windows (KB5074109) in the list.
5. Click Uninstall next to it.
6. Restart your computer.

When you open Outlook after the restart, it may take a few minutes to perform a "consistency check" on your data file. Once this finishes, your Sent Items should reappear, and your deleted emails should finally stay deleted.

Tip: To prevent Windows from automatically reinstalling this update tonight, go to Settings > Windows Update and click "Pause updates for 1 week." This will keep your system stable until the official permanent fix is released.

I hope rolling back this specific update restores your Outlook stability while the engineering team prepares the permanent patch. I will follow up with you here as soon as the permanent fix is released so you can safely update again.

Thank you for your patience and understanding while Microsoft is working on the solution.

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Answer 2

It sounds like you're experiencing multiple issues with Outlook following a recent Windows update. Here are some potential causes and resolutions:

1. Outlook Not Responding: This can occur due to various reasons, including outdated software, conflicts with other processes, or corrupted data files. Make sure you have the latest updates installed for both Windows and Outlook.
2. Sent Emails Not Showing: This could be related to synchronization issues with your email server. Ensure that your account settings are correct and that Outlook is properly connected to your email server.
3. Emails Not Deleting: If emails are not deleting, it may indicate a problem with your mailbox or a conflict with an add-in. Try disabling any unnecessary add-ins and check your mailbox size.
4. Emails Showing as New: This issue might arise if Outlook is not syncing correctly with the server. Check your account settings and consider repairing your Outlook data files using the Inbox repair tool (scanpst.exe).

To resolve these issues, you can follow these steps:

• Install the latest updates for Outlook and Windows.
• Repair your Office programs through the Control Panel.
• Use the Inbox repair tool to fix any corrupted data files.
• Check your antivirus software to ensure it’s up-to-date and not conflicting with Outlook.

If the problems persist, consider running the Classic Outlook Advanced Diagnostics troubleshooter to automatically check for common issues.

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References:

• Outlook not responding error or Outlook freezes when you open a file or send mail
• Outlook not responding error or Outlook freezes when you open a file or send mail