Microsoft "new" Teams - Messages won't send until I quit program

Hi @Sidney Borghino,

Thank you for your detailed update.

We're really sorry for the inconvenience that may have caused you.

This is a known issue in the new Microsoft Teams desktop client, likely linked to corrupt local user data, network sync failures, or broken app state in the Windows app container.

Here're suggestions you can try:

1. Fully remove new Teams app + hidden app data

The new Teams (v2) is a UWP/Windows Store app, which leaves residual data even after reset.

Uninstall Teams (New Version)

• Go to Settings > Apps > Installed apps
• Find Microsoft Teams (the one installed from Microsoft Store)
• Click Uninstall

Delete hidden Teams app data

Open File Explorer, paste each of these paths in the address bar one at a time and delete any folders if they exist:

%userprofile%\AppData\Local\Packages\MSTeams_8wekyb3d8bbwe %userprofile%\AppData\Local\Microsoft\Teams %userprofile%\AppData\Roaming\Microsoft\Teams

You may need to enable hidden items in the View tab to see some folders.

Restart your PC

2. Reinstall the Classic Teams App (Legacy Desktop version)

The new Teams client (v2) has known issues on Windows 10, especially on low-resource or low-storage devices.

Try using the classic (Electron-based) Teams client, which is still supported and more stable on some setups:

• Download link: Download Microsoft Teams for Windows
• Install and sign in

Test message sending. Many users have found the classic version more reliable when the new version fails.

3. Create a support ticket

• Go to Three dots at the top-right corner
• Choose Feedback > Report a problem

• After submitting a support ticket, you can also share the ticket number with us if you want. We will also monitor the progress from our end.

Looking forward to your response and have a great day ahead.

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Hi @Sidney Borghino,

Thank you for posting your question in the Microsoft Q&A forum.

It sounds like you're experiencing a persistent issue in the new Microsoft Teams on Windows 10, where messages won’t send unless you fully quit and restart the app.

To better understand the problem, may I kindly ask you to provide the following details:

• Are you using the desktop app or the web version of Teams?
• Have you tried sending messages through the web version to see if the issue persists?

In the meantime, you can try these additional steps to troubleshoot your issue: 

1. Fully clear the cache (New Teams)

• Quit Teams completely.
• Press Windows + R , type:

%userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams

• Delete all files and folders in that directory.
• Restart Teams.
• For your reference: Clear the Teams client cache

2. Update Teams manually

• Open Teams.
• Click three dots at the top-right corner > Settings > About Teams

• Let it install and restart the app. Outdated versions can cause sync issues.

3. Try the web version

• Go to https://teams.microsoft.com and log in.
• If messages send fine there, the issue is likely with the desktop app.

4. Check firewall settings

• Go to Control Panel > Windows Defender Firewall > Allow an app or feature through  Windows Defender Firewall
• Make sure Microsoft Teams is allowed on both Private and Public networks.

Note: Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. 

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this. 

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out. 

I'm looking forward to your reply. 

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This has been happening to me for about 6 months now and this does NOT resolve the issue.

Now I have several other colleagues to which this is happening.

Are you telling me that every other day I'm going to have to go teach a bunch of tech-illiterate people how to walk through the steps you posted? Our admin team already uses a secondary chat we can all trust -- do we just need to migrate away from Microsoft products, or what?

Your stuff is a mess and has been for so long that I no longer recommend Mac users switch over to Microsoft.

Fix it.

Hi @Sidney Borghino,

It's wonderful news that your issue has been resolved. I truly appreciate your effort in finding a resolution. I believe that many users may encounter similar issue, and your case could serve as a valuable reference for them.   

Therefore, I would make a brief summary of this post so that other forum members could easily find useful information here:  

Issue Description:

In the new Microsoft Teams app for Windows, messages failed to send unless the user manually quit and restarted the application. Incoming messages and notifications worked fine, but outgoing messages - including reactions - would freeze or remain unsent.

Assessment:

Troubleshooting steps included:

• Reinstalling the Teams app
• Restarting the computer
• Attempting to upgrade to Windows 11 (blocked due to low storage)
• Clearing the Teams cache (temporary fix)

The issue persisted after switching chats or sending multiple messages.

Resolution:

Upgrading from Windows 10 to Windows 11 resolved the issue. After the upgrade, Teams began functioning normally, with messages sending instantly.

More Information:

This issue may be related to compatibility or resource limitations in the new Teams client on Windows 10. If you're experiencing similar problems:

• Clear the Teams cache regularly
• Ensure you're using the latest version of Teams
• Consider upgrading to Windows 11 if supported by your device.

As other users may search for similar issues in this forum, your post and solution will be a helpful reference. If you found this helpful, consider voting or marking it as a solution to make it easier for others to find.

We truly appreciate your time and cooperation throughout the resolution of this matter. Thank you for being a valued customer and for contacting us on the Microsoft Q&A forum.

If you need any other assistance, please don’t hesitate to reach out again and I would be happy to help you.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".  

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I went into the storage settings, cliked on apps, clicked on teams, and advanced options, then I hit "repair " and "reset". My teams worked for a bit then same error sending messages.