Fix Teams Cannot Start a New Chat after Moving to New Teams

After you switch from classic Teams to the new Teams app, starting a new chat may fail. The compose box stays empty, the New chat button does nothing, or an error message appears. This problem usually comes from a corrupted local cache or a stale profile that the new Teams app inherited. This article explains the root cause and gives you step-by-step fixes to restore chat functionality.

The new Teams app stores its data in a different folder than the classic version. When the migration process copies your old settings, some files can become corrupted or incompatible. This leads to a broken chat composer. You will also learn how to avoid common mistakes and how to verify that your fix worked.

Why the New Chat Button Fails After Migrating to New Teams

The new Teams app is a separate application from the classic Teams client. It uses a different installation path and stores user data in a new location. When you move to new Teams, the app tries to copy your profile and settings from the old version. This migration process can fail silently, leaving behind corrupted cache files or an incomplete user profile.

The chat composer relies on a local database that stores your conversation history and contacts. If this database is damaged, the New chat button may appear grayed out or simply do nothing when clicked. Another common cause is a conflict between the old and new Teams versions. If both apps are installed at the same time, they can interfere with each other’s data.

What Happens During the Migration

When you first launch new Teams, it detects your classic Teams profile and copies it to a new folder. This copy process is not always perfect. Some files may be locked by the old app, or the migration may be interrupted. The result is a broken chat service that cannot start new conversations.

How to Confirm the Problem

Open the new Teams app and try to start a new chat. If the compose box does not appear, or if you see an error message like “Something went wrong,” the cache is likely corrupt. You can also check the Teams version by clicking your profile picture and selecting About. If you are still on classic Teams, you have not completed the migration.

Steps to Fix the New Chat Problem in New Teams

Follow these steps in order. Each step addresses a different cause. Test after each step to see if the problem is resolved.

1. Close Teams completely
   Right-click the Teams icon in the system tray and select Quit. Make sure no Teams process is running in Task Manager. Press Ctrl+Shift+Esc to open Task Manager, look for any Teams entry, and click End task.
2. Clear the Teams cache folder
   Press Windows+R, type %appdata%\Microsoft\Teams, and press Enter. Delete all files and folders inside this directory. Do not delete the Teams folder itself. This removes corrupted cache files that block the chat composer.
3. Clear the new Teams cache folder
   Press Windows+R, type %appdata%\Microsoft\Teams\Service Worker, and press Enter. Delete everything inside this folder. The new Teams app stores additional data here, and clearing it can fix chat issues.
4. Restart your computer
   Reboot your PC to ensure that all Teams processes are fully terminated and that the system clears any temporary locks.
5. Reinstall the new Teams app
   Open Settings > Apps > Installed apps. Find Microsoft Teams, click the three-dot menu, and select Uninstall. Then go to the Microsoft 365 admin center and download the new Teams installer. Run the installer and sign in with your work account.
6. Check your messaging policies
   Go to the Teams admin center. Navigate to Messaging policies. Select the policy assigned to your user and confirm that the Chat option is set to On. If it is Off, change it to On and save the policy.
7. Verify the fix
   Open the new Teams app and try to start a new chat. If the compose box appears and you can send a message, the fix worked.

If Teams Still Has Issues After the Main Fix

Teams Shows a Blank Window After Clearing the Cache

Clearing the cache can sometimes cause Teams to open as a blank window. This happens because the app needs to rebuild its local data. Wait a few minutes for the app to synchronize. If the blank window persists, sign out and sign back in. This forces a fresh download of your profile data.

The New Chat Button Is Grayed Out

A grayed-out New chat button usually means your messaging policy blocks chat. Contact your Teams administrator to check your assigned policy. The administrator can also apply a different policy that allows chat.

Chat Works in Classic Teams but Not in New Teams

If classic Teams works but new Teams does not, the migration may have copied a corrupt profile. Uninstall new Teams completely, then reinstall it. Do not sign in to classic Teams again before you test new Teams, because that can trigger another bad migration.

New Teams vs Classic Teams: Chat Experience Comparison

Item	New Teams	Classic Teams
Installation path	%appdata%\Microsoft\Teams	%LocalAppData%\Microsoft\Teams
Cache location	%appdata%\Microsoft\Teams\Service Worker	%appdata%\Microsoft\Teams
Chat composer	Uses a new local database	Uses the legacy database
Migration behavior	Copies profile from classic	No migration needed
Known chat issues	Corrupt cache after migration	Rarely affected

Conclusion

You can now restore the New chat function in new Teams by clearing the cache, reinstalling the app, and checking your messaging policy. Start with the cache clear because it is the fastest fix. If that does not work, reinstall the app and verify your policy settings.

After the fix, test the chat composer with a single message to confirm everything works. Then explore the new chat features like @mentions and message formatting. For advanced troubleshooting, use the Teams diagnostic tool in the admin center to check for other policy conflicts.