How to Fix Outlook Issues After Windows 11 KB5074109 Update [4 Ways]

Overview of Windows 11 KB5074109 Oulook Issues

Windows 11 KB5074109 is now available for versions 25H2 and 24H2. However, after installing this update, a serious issue has been reported with Outlook Classic (the newer web-based Outlook won't be affected).

Specifically, users who use Outlook POP account profiles or profiles with PST files have reported that Outlook freezes and fails to close properly after KB5074109 update. This problem can affect any Outlook profile with PST files stored on OneDrive.

▼Symptoms Include:

• Outlook cannot close properly and cannot be restarted.
• Outlook freezes and hangs not responding.
• The same email is received multiple times.
• Read emails revert to an unread state.
• Sent emails do not appear in the Sent Items folder even though they were successfully sent.
• Outlook won't be able to re-download emails.

▼What causes Outlook Freezes:

According to Microsoft’s official announcement, this issue is caused by a compatibility problem between the KB5074109 security update and Outlook’s handling of POP account profiles. The Microsoft Outlook and Windows teams are currently investigating the issue and are working on a fix.

How to Fix Oulook Issues After Windows 11 KB5074109 Update

If you run into the same Outlook issue after updating to KB5074109, there are four ways to fix the problem. Please try them one by one.

1 Boot into Safe Mode

The first thing you should try is launching Outlook in Safe Mode. This is a diagnostic mode that starts the application with add-ins and extensions disabled.

Boot into Safe Mode Using Ctrl Key

• Close Outlook completely, make sure it’s not running in the background.
• Press and hold the Ctrl key on your keyboard.
• While holding Ctrl, click the Outlook icon to open the app.
• Keep holding Ctrl until a confirmation dialog appears.
• When prompted, click "Yes" to confirm that you want to start Outlook in Safe Mode.
• Outlook will launch with add-ins and extensions disabled.

Boot into Safe Mode with Command

• Press Win + S and type Command Prompt, then open it.
• Type the command: outlook.exe /safe and press Enter.
• Outlook will launch in Safe Mode.

If Outlook runs normally in Safe Mode, the issue is likely caused by a problematic add-in or extension.

2 Use Outlook Webmail

Microsoft recommends that, users can switch to Outlook webmail until a fix is released. This helps minimize the risk of encountering Outlook-related issues caused by the update.

Although the web version differs slightly from the desktop app, please use it to send and receive emails online until the latest update is released. This will ensure your work is not interrupted.

3 Uninstall KB5074109

If Outlook continues to malfunction, the next step is to uninstall the KB5074109 update. This is the recommended approach, as removing an unstable update is often the safest and quickest solution whenever an update causes problems. It can restore normal Outlook functionality immediately while you wait for Microsoft to release a fix.

• Open "Settings > Windows Update > Update history > Uninstall updates".
• Look for KB5074109 and click “Uninstall.”
• Confirm the action and Windows will uninstall and reboot automatically.

4 Move PSTs Out of OneDrive

If your Outlook profile contains PST files stored in OneDrive, moving them to a local folder is a highly effective way to prevent syncing-related issues. This step can help stabilize Outlook while you wait for an official fix from Microsoft.

• Press Win + E to open File Explorer.
• Go to OneDrive and find your Outlook PST files. The common locations include:
  • OneDrive\Documents\Outlook Files
  • OneDrive\Outlook Files
• Create a new local folder on your PC, then copy or move the PST files from OneDrive to this folder.
• Open Outlook and go to "File > Account Settings > Account Settings".
• Select "Data Files" and remove the old PST file linked to OneDrive.
• Click "Add", then browse to the new local folder you just created and select the PST file.
• Click "OK" and restart Outlook to ensure everything works normally.

How to Recover Lost Emails After KB5074109 Update

The KB5074109 Outlook bug may lead to email loss. In such cases, you can use professional data recovery software to restore the missing emails.

Compatible with Windows 11, Tenorshare 4DDiG is a powerful data recovery tool that uses AI-powered algorithm to recover lost Outlook email data (such as .pst and .ost files) lost due to system crashes and improper Windows update, allowing you to recover lost emails with just a few simple steps.

• Supports Multiple Data Types: Restore 2,000+ file types, including emails, photos, videos, audio, documents...
• Various Storage Support: Recover files from HDD/SSD, USB drive, SD card and more.
• Different Scenarios: It can recover data lost in many situations, such as accidental deletion, formatting, lost partitions, or a crashed computer.
• Free Preview Feature: Lets you preview the recoverable files before the recovery process.
• Deep Scan & High Success: Able to deep scan your drive for all the lost emails, with up to 99.8% success rate.
• User-friendly: Simple and intuitive design suitable for both beginners and advanced users.

Steps to use 4DDiG for drive data recovery:

• Launch 4DDiG Data Recovery on your computer, choose the drive that contains the lost email and start scanning.
• Wait for a few minutes for the emails to show up. You can also use the tree view to search for the file you need to recover.
• You can double-click the email, photo, video or document you want to recover to have a quick preview. Then click the "Recover" button.
• Select the emails you want to recover and choose a save location, then click "Save Now". You can consider saving them to cloud drive.

Conclusion

The Outlook issues caused by the Windows 11 KB5074109 update are a serious problem affecting many users. This article outlines four main solutions: starting Outlook in Safe Mode, using webmail, uninstalling the update, and moving PST files out of OneDrive. Please try them in order.

If your emails are lost due to the issue, you can use 4DDiG Data Recovery to recover your missing emails. 4DDiG offers a high recovery success rate and an easy-to-use interface, making it safe and accessible for even beginners.