Why Teams Can’t Schedule Meetings with (Some) Teams

Teams are Built on Groups and Some Groups are Hidden

In April 2018, Microsoft decided to hide the Office 365 Groups (now Microsoft 365 Groups) created by Teams from Exchange address lists. At the time, the logic was impeccable. The Groups created by Teams didn’t need to be visible to Exchange clients because Teams is used for conversations rather than email, so it made sense to hide those groups. Teams marks the groups it creates as not available to Exchange clients by setting the HiddenFromExchangeClients property to $True.

Setting the property means that the hidden groups are excluded from the address lists used by Exchange clients. The lists include the Global Address List and All Groups, used by clients like Outlook, OWA, and Outlook mobile to validate addresses entered in messages. Groups created in SharePoint, Planner, Stream, or Yammer are available to Exchange clients, as are those groups created by an Exchange client. All these groups are visible in the GAL and All Groups list (Figure 1), but the groups created by Teams are not.

The Problem for Teams Meetings

Microsoft made the change, Exchange clients didn’t notice that the groups used by Teams had disappeared, and all was well. That is, until May 15 when Microsoft announced that the attendee picker used by the Teams calendar app now includes Exchange Online distribution groups and Microsoft 365 Groups.

The problem now exposed by the law of unintended consequences is that users cannot schedule meetings with a team (to invite all members) because the attendee picker used by the Teams calendar app is based on Exchange address lists, which means that the hidden groups aren’t shown. The reason why people want to schedule a meeting with team members is that they want each member to receive a meeting invitation in the same way that members of a distribution list receive invitations when a meeting is scheduled from Outlook.

You could argue that arranging a meeting in a team channel serves the same purpose, but channel meetings don’t generate individual invitations for users. Details of those meetings go into the group mailbox for the team that the channel belongs to.

Teams Calendar App Only Schedules with Visible Groups

The Teams calendar app allows some Teams to be selected because their HiddenFromExchangeClients property is set to $False. For instance, this command finds the set of team-enabled groups in a tenant:

$Groups = Get-UnifiedGroup -Filter {ResourceProvisioningOptions -eq "Team"} -ResultSize Unlimited

In my tenant, I have 66 team-enabled groups. When I checked how many were hidden by running:

$HiddenGroups = $Groups |? {$_.HiddenFromExchangeClientsEnabled -eq $True}

I found that 27 are hidden but 39 are listed in the GAL. Cue the potential to confuse users when some teams can be used to schedule meetings, and some cannot. The reason why some groups are hidden and others are not is probably linked to the age of the group. Team-enabled groups created before April 2018 are likely not hidden while those created afterwards are hidden, unless someone has changed the flag with PowerShell using a command like:

Set-UnifiedGroup -Identity MyGroup -HiddenFromExchangeClientsEnabled:$False

Group Subscriptions Decide Who Receives Event Notifications

However, it’s not just a matter of exposing groups to Teams as other settings control who receives invitations to meetings sent to the group. Each group has a subscriber list to determine who receives messages sent to the group, including invitations to events. When an event is scheduled with a group, Exchange Online sends invitations to the members on the group’s subscriber list whose subscription indicates they wish to receive copies of calendar events. Group owners and administrators can update settings which control subscriptions with PowerShell.

The AutoSubscribeNewMembers property controls if new members are automatically added as subscribers.

Set-UnifiedGroup -Identity MyGroup -AutoSubscribeNewMembers:$True

The AlwaysSubscribeMembersToCalendarEvents switch can be used to control what events users receive. Members of a team probably are probably only interested in calendar events, so you can run this command to instruct the group to restrict the subscription for new members to events.

Set-UnifiedGroup -Identity MyGroup -AlwaysSubscribeMembersToCalendarEvents

Individual members can override the default settings for the messages they wish to receive from a group by changing their Follow in Inbox settings after selecting the group in OWA or Outlook. Figure 3 shows how to change the settings in Outlook for Windows. To receive meeting notifications, the user selects either All Email and Events or Only Replies to You and Events.

Existing members might not be subscribed to the group. In this case, you can add people to the subscriber list:

Add-UnifiedGroupLinks -LinkType Subscriber -Links Kim.Akers -Identity MyGroup

Or take all members of the group and add them to the subscriber list:

$Members = Get-UnifiedGroupLinks -LinkType Members -Identity MyGroup
Foreach ($M in $Members) {
    Add-UnifiedGroupLinks -LinkType Subscribers -Links $M.PrimarySmtpAddress -Identity MyGroup }

After users are added as subscribers, they receive invitations to new calendar events.

In summary

Microsoft 365 Groups give a lot to Teams, but their history and some of the changes made since their introduction occasionally throw up conflicts like this between the way Groups were designed to work with Outlook and how Teams would like them to work. If you want to schedule meetings with Teams, make sure that the group belonging to the teams aren’t hidden from Exchange address lists. Or create and send meeting invitations with Outlook to the group’s SMTP address.

But if you want team members to receive personal invitations for events sent to the group, add them to the group’s subscriber list or add them as individual attendees to the meeting invitation. Clear as mud!

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