Tenant wide way to stop new Office365 Groups appearing in Exchange Online GAL

Occasional Contributor


We have come across an issue that many are facing - namely Office 365 Groups created via various Office 365 apps (Planner, Teams, SharePoint, etc) have made a mess out of our Exchange Online GAL.

I know there is a PowerShell command to hide the Office 365 Group from GAL after it's created:

Set-UnifiedGroup -Identity *** group email address*** -HiddenFromAddressListsEnabled $true

I want to know if there is a way to stop if BEFORE the Group is created. Is there a tenant wide setting to achieve this? Can we use Group Classification to this end? Is there a good reference that covers O365 Groups Classification? I only found one so far:

6 Replies


I'm getting increasingly frustrated by this myself. I can appreciate the approach to empower users to create their own plans, groups and teams but one size does not fit all.


I can't believe the controls have not been created within the Admin GUI to to disable this by default. We shouldn't need to rely on scheduled Powershell tasks to make these type of amendments. 


While we would like users to be able to create their own plans (Hidden from the GAL by default), we do not want Groups and Teams created ad infinitum without some thought behind the process. With this open approach 365 can quickly become a dumping ground for "Test Team" and "Test Group"  experiments by end users. 


As with a lot of new Microsoft products, its a case of great technology but lack of thought behind the governance of these features.

best response confirmed by Alex Ouretski (Occasional Contributor)

There has been some movement on this topic recently, with plans announced to clean up the clutter created by Groups/Teams in Outlook ( As for cleaning up the GAL, I haven't heard anything, but I would definitely appreciate an option similar to the Mailbox plans we have for regular mailboxes, where we can preconfigure some settings.

We too feel that the addition of groups to the GAL is creating a mess.  We would like Microsoft to address this and prevent items from being shown in the GAL by default (much like they finally changed in Teams).

@RSAdmin2315 It looks like this will be a major issue for millions of users worldwide using O365 and Exchange Online. Are there any updates on this or is Microsoft just ignoring the issue for now?

At my company student are creating around 250 groups a week.

We had the same issue with the groups showing up in the GAL

Also we found that some names like (management) were also used in the newly created groups, leading to confusing which one was the right mail address.


Now I have a script running every hour that gets all the groups and then it does the following (snippet):


$GALshownGroups = Get-UnifiedGroup -ResultSize Unlimited -Filter {CustomAttribute2 -eq $null}

foreach ($group in $GALshownGroups){
Set-Unifiedgroup -identity $group.PrimarySmtpAddress -CustomAttribute2 "GALhidden" -HiddenFromAddressListsEnabled $true


The custom attribute is used to store if the group has been processed. Some groups are allowed to be visible so I only get the groups that have nothing filled there. That way I don't have to retrieve all the groups.


Would be a lot better ofcoz that HiddenFromAddressListEnabled can be set to a default value that you can change based on the companies policy

@Adm_MaikelS null 

Thanks for the tip.  Still a bit ridiculous that we're all "working around" this fundamental problem.  Microsoft really needs to address this.  The GAL has been a critical component of organization's for years -- allow it to devolve into a wasteland for IT administrators to chase clean-up of is disappointing.