Resolve issues that affect the Teams Meeting add-in for classic Outlook

If you're a Microsoft Teams administrator, and your users can't install the Teams Meeting add-in for classic Outlook, schedule Outlook meetings from Teams, or schedule Teams meetings from Outlook, the issue might be caused by a problematic installation of the Teams Meeting add-in, a switch from classic Teams to new Teams, or because the users' mailboxes are hidden from the Global Address List (GAL).

Teams Meeting add-in is missing or its installation fails

If you've configured the add-in for all users but it's missing for some users, try the following steps to troubleshoot and resolve the issue.

Check the status of the add-in in Outlook

Make sure that the Teams Meeting add-in is enabled in Outlook.

1. In Outlook, select File > Options.
2. In the Outlook Options dialog box, select the Add-ins tab.
3. Check whether Microsoft Teams Meeting Add-in for Microsoft Office is in the Active Application Add-ins list.
4. If the add-in isn't in the list of active applications, and you see the Teams Meeting add-in in the Disabled Application Add-ins list, select Manage > COM Add-ins, and then select Go.
5. Select the checkbox that's next to Microsoft Teams Meeting Add-in for Microsoft Office.
6. Select OK on every open dialog box, and then restart Outlook.

Reregister the Teams Addin Loader

Use the following steps:

1. Verify that users have the Teams desktop client installed. The meeting add-in can't be installed if you use only the Teams web client.

2. Verify that users are running Outlook 2016 or a later version.

3. Verify that all available updates for the Outlook desktop client are applied.

4. Exit Outlook.

5. Exit Teams.

6. Reregister Microsoft.Teams.AddinLoader.dll:

   1. Open File Explorer, and then navigate to the %LocalAppData%\Microsoft\TeamsMeetingAddin folder.
   2. Select the subfolder that has a name that's the same as the version number. If there are multiple subfolders that have the same version number, select the subfolder that has the highest build number. Then, copy the path of this subfolder. For example, %LocalAppData%\Microsoft\TeamsMeetingAddin\1.0.23334.11.
   3. Open an elevated Command Prompt window, and then run the following command that's appropriate for your Office installation:

   • For 64-bit Office

     %SystemRoot%\System32\regsvr32.exe /n /i:user <path copied in step b>\x64\Microsoft.Teams.AddinLoader.dll
     

   • For 32-bit Office

      %SystemRoot%\SysWOW64\regsvr32.exe /n /i:user <path copied in step b>\x86\Microsoft.Teams.AddinLoader.dll
     

7. Restart the Teams desktop client.

8. Sign out and then sign in to the Teams desktop client.

9. Restart the Outlook desktop client. Make sure that Outlook isn't running in Administrator mode.

Verify registry settings

If the add-in still doesn't appear, follow these steps to check the registry settings.

1. Check the load behavior of the add-in:

   1. Open RegEdit.exe.
   2. Navigate to HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\Outlook\Addins\TeamsAddin.FastConnect.
   3. Check the value of the LoadBehavior entry. It should be set to 3.
   4. If LoadBehavior has a value other than 3, change it to 3, and then restart Outlook.

   If the add-in still doesn't appear, go to step 2.

2. Check whether the Configure Outlook object model prompt when reading address information policy setting is configured:

   1. Open RegEdit.exe.

   2. Navigate to HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\Security. If you applied the policy settings by using Cloud Policy service, navigate to HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Cloud\Office\16.0\Outlook\Security.

      Note: Policy settings that are implemented by using Cloud Policy take precedence over policy settings that are implemented by using Group Policy on Windows.

   3. Check for the promptoomaddressinformationaccess registry entry and whether a value is set for it. If the value is 0, this indicates that the policy setting is set to the Automatically deny option. If it is, Outlook will automatically deny programmatic access requests from any program. In this situation, go to step 2d.

   4. Check the Configure trusted add-ins policy setting.

      If this policy setting is configured, Teams administrators can use one of the following options:

      • Disable or unconfigure the policy setting.

      • If the policy is required, make sure that Microsoft.Teams.AddinLoader.dll is in the list of trusted add-ins and that the corresponding hash value is correct. You can use the Get-FileHash cmdlet to compute the hash value of the .dll file.

        Note: The Microsoft.Teams.AddinLoader.dll file that's used is automatically updated with the Teams client. Therefore, the hash value must be constantly updated to pair with the .dll file.

Teams Meeting add-in is missing after updating from classic Teams to New Teams

Either you or your organization uninstalls classic Teams and then upgrades to new Teams. You uninstall the program by using one of the following methods:

• Any of the available options to uninstall programs in Windows 11 and Windows 10.
• An administrative policy that triggers the removal of classic Teams. For example, organizations might choose to remove older versions of classic Teams from user computers to make sure that most users are on the same version.
• The "new Teams only" policy setting to upgrade to new Teams. When a user is assigned this Teams upgrade policy, the new Teams app removes the classic Teams app from the user's computer after a set time.

After the upgrade, the Teams meeting add-in doesn't load and the add-in is removed from Outlook.

To reinstall the Teams meeting add-in in non-VDI environments, follow these steps:

1. Quit Teams.

2. Close the Outlook app.

3. Check the version of the Teams meeting add-in.

   To check the Teams meeting add-in version, select Start > Settings > Apps > Installed apps, and then enter Teams Meeting Add-in in the search box.

   • If no result is found, or the version of Microsoft Teams Meeting Add-in for Microsoft Office starts with 1.23, follow these steps:

     1. Download the UninstallOldTMA.ps1 PowerShell script.
     2. Open an elevated PowerShell window. To open the window, enter powershell in the search box. In the results, right-click Windows PowerShell, and then select Run as administrator.
     3. At the elevated PowerShell prompt, run the UninstallOldTMA.ps1 script to uninstall the Teams meeting add-in.

   • If the version of Microsoft Teams Meeting Add-in for Microsoft Office doesn't start with 1.23, follow these steps:

     1. Download the UninstallTMA.ps1 PowerShell script.
     2. Open a PowerShell window. To open the window, enter powershell in the search box. In the results, select Windows PowerShell.
     3. At the PowerShell prompt, run the UninstallTMA.ps1 script to uninstall the Teams meeting add-in.

4. Start the new Teams app.

5. Wait until the Teams meeting add-in appears in the list in Start > Settings > Apps > Installed apps.

6. Restart the Outlook app.

Details to join a meeting are missing

When a delegate schedules a Teams meeting in a delegated calendar on behalf of the delegator, the following meeting join details aren't added to the body of the meeting request:

• Meeting URL
• Meeting ID and passcode
• Dial-in numbers

This issue occurs if the delegator's mailbox is hidden from the global address list (GAL). In this case, the Teams Meeting add-in can't get the required information to populate the meeting details.

To fix the issue, run the following Exchange Online PowerShell cmdlet to unhide the delegator's mailbox:

Set-Mailbox -Identity <delegator’s email address> -HiddenFromAddressListsEnabled $false

Verify that the mailbox is visible in the GAL. Then, ask the delegate to restart Outlook and create a new meeting request.