Stopping Microsoft Teams Posting System Messages About New Members

No Way to Suppress Messages

A reader asked if it’s possible to stop Teams displaying a system-generated message when someone joins a team. It’s a reasonable question. In the past, I have pointed out the dangers of adding someone to a group too early as people can then discover that a new employee is joining the company. Conversely, it’s not good when people learn about the departure of a valued colleague through an informational message posted in Teams to say that the person has left a team.

Things used to be worse. Before May 2020, Teams posted messages about members joining and leaving a team in the team’s General channel. The introduction of the channel information pane gave these system messages a new home. Unless people open the information pane, they don’t see messages about membership changes, new owners and channels, and other developments, so there’s a fair chance that the addition of a new employee to a team will go unnoticed.

The Many Ways to Add New Members to a Team

To see any of the methods to add a new member do not result in a system message in the information pane, I tested by adding a new member through:

  • The Teams client.
  • The Add-UnifiedGroupLinks cmdlet from the Exchange Online management module.
  • The Add-AzureADGroupMember cmdlet from the Azure AD module.
  • The Add-TeamUser cmdlet from the Microsoft Teams module.

I didn’t test using the Microsoft Graph API. The Add-TeamUser cmdlet is a wrapper around the Graph API call, so the results observed for that cmdlet are likely the same for a Graph call. System messages are retrievable using Graph API calls.

Azure AD is the directory of record. Add-AzureADGroupMember updates the Azure AD group object used by the team. Add-UnifiedGroupLinks updates the Azure AD group object and the group in the Exchange Online directory using a dual write. Add-TeamUser is like adding a new member through the client because the action updates both the team roster (to make the new team member immediately available) and Azure AD. Rosters (lists of members and owners) are how Teams organizes and manages membership.

Changes made to Azure AD or by other Microsoft 365 workloads synchronize with Teams through a background process called Microsoft Teams Aad Sync, introduced in 2020 to make the synchronization process between Teams and Azure AD more efficient and effective. Note that it can take several hours before a system message about a new member shows up. Apart from the need to run background synchronization, clients also need to refresh their cache.

In a nutshell, no matter how you add or remove a tenant or guest account, the change synchronizes back to Teams and the system message appears in the information pane (Figure 1).

System messages about membership changes appear in the information pane
Figure 1: System messages about membership changes appear in the information pane

Different system messages in the information pane appear depending on the method used to add an account. If you see that someone added a member (like “Tony Redmond has added Niamh Smith to the team”), it’s an indication that the action occurred through the Teams client, the Add-TeamUser cmdlet, or the Graph API (all of which execute the same code). On the other hand, if you see that someone joined the team, the source is Azure AD or Exchange Online PowerShell.

No Control Over System Messages

There’s no system or team setting to tweak to turn off system messages about member updates. Granular control would be best, but I guess Microsoft ignored me when I previously complained about the lack of control over system message publication, so I’ve submitted it again to the new Teams Feedback portal. Please vote there if you support the idea of having a team-level setting to control the publication of system messages.

In the interim, if you don’t want other users to discover that someone has joined a team, either wait until an appropriate time before adding them as a member or consider assigning a new display name to that person’s account until you’re ready to reveal their presence. For instance, I changed the name of a new user as follows:

Set-AzureADUser -Identity -DisplayName "The Maestro of Office 365"

After waiting for a few hours to allow Teams to pick up details of the user account, I added them to a team. Sometime later, the information pane duly displays the system message for the addition (Figure 2):

Obscuring the addition of a new team member
Figure 2: Obscuring the addition of a new team member

This technique works if you want to pre-add new users to teams before they join the organization if you use suitably obscured display names, like UserAXXAD19948. Naturally, you should update their display name after they’re active in the organization. However, it’s not a great approach for people who already work there as other workloads pick up and use the changed display name.

Small Detail

The answer to the original question is that you can’t stop Teams posting system messages to inform team members about membership changes. No control is available at a system or individual team level, which is a pity. But life isn’t perfect, and this is a small detail in the overall scheme of things – unless you inadvertently reveal the name of a new employee before they join the company.

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