Microsoft Teams, both "Classic" and "New", can perform slowly overtime on both Windows and MacOS when the cache becomes too large.

Resetting the app or clearing cache files can help improve performance or fix meeting issues.

Clear the cache in Teams for Windows

Classic Teams

1. If Teams is still running, right-click the Teams icon on the taskbar, and then select Quit.
2. Open the Run dialog box by pressing the Windows key + R.
3. In the Run dialog box, enter the following path, and then select OK:

   %appdata%\Microsoft\Teams

4. Delete all files and folders in the directory.
5. Restart Teams.

New Teams

Method 1: Reset the app

Note: When you reset the Teams app, the app data will be deleted. This includes any personalization settings that you might have configured.

1. Type settings in the search box, and then select the Settings app from the results.
2. Select Apps > Installed apps, and then type Microsoft Teams in the search box.
3. Locate the New Microsoft Teams app from the results, select the More options button (...) on the right, and then select Advanced options.
4. In the Reset section, select Reset.
5. Restart Teams.

Method 2: Delete the files

1. If Teams is still running, right-click the Teams icon on the taskbar, and then select Quit.
2. Open the Run dialog box by pressing the Windows key + R.
3. In the Run dialog box, enter the following path, and then select OK.

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

4. Delete all files and folders in the directory.
5. Restart Teams.

Clear the cache in Teams for macOS

Classic Teams

1. If Teams is still running, right-click the Teams icon in the dock, and then select Quit or press Command (⌘)-Q.
2. In the Finder, open the /Applications/Utilities folder, and then double-click Terminal.
3. Enter the following command, and then press Return:

   rm -r ~/Library/Application\ Support/Microsoft/Teams

4. Restart Teams.

New Teams

1. If Teams is still running, right-click the Teams icon in the dock, and then select Quit or press Command (⌘)-Q.
2. In the Finder, open the /Applications/Utilities folder, and then double-click Terminal.
3. Enter the following commands, and press Return after each command:

   rm -rf ~/Library/Group Containers/UBF8T346G9.com.microsoft.teams

   rm -rf ~/Library/Containers/com.microsoft.teams2

4. Restart Teams.