Deprecation of Site Mailboxes

In March 2017, we took the first step towards deprecating site mailboxes by announcing that we will stop the creation of new ones. Today you can no longer create site mailboxes and over time we will stop support for the product completely.


Site mailboxes offered a great way to augment the collaboration options available on a SharePoint site. Despite people turning to site mailboxes to satisfy their email based collaboration needs, we have not seen the level of adoption that we would have liked. We have in fact, seen a declining trend over the years despite our best efforts to promote site mailboxes. To the customers who did use site mailboxes regularly, we appreciate your commitment towards our product and value your partnership. We understand that this decision will be disappointing for a few of you. But after a lot of internal deliberation, we have decided to deprecate site mailboxes and invest in Office 365 groups.


Office 365 groups go beyond just providing a shared inbox space by having a shared documents library, a shared calendar, a shared notebook and a lot more. See Learn about Office 365 Groups to know more. Groups are self-served and give more power to end users to actively collaborate among themselves. Whether you want to set up a small project team or a large helpdesk, Office 365 groups work great in all scenarios. In its short duration of existence, groups have already seen a much larger adoption than site mailboxes. This, coupled with the ability to associate a group with a SharePoint team site make Office 365 groups the ideal replacement for site mailboxes.


We understand that we have a lot of customers still actively using site mailboxes and that this deprecation will affect their day to day operations. We assure such customers that we are working on providing a solution for the transition process. By the end of 2017 we will have a process in place which will let you connect your classic experience SharePoint team site to an Office 365 group. As a start, you can check out Use Office 365 Groups instead of Site Mailboxes to know how to move to groups.


We are grateful for the continued patronage our customers have shown us and we hope to extend this into the future as well. Do reach out to us if you have any questions or concerns.


Super Contributor
Hi Mohammad, You mention '...over time we will stop support for the product completely.' This is somewhat vague in nature. Can Microsoft be more precise? You state you are working on a transition process but give no timelines for publishing this. However small the customer contigent often a long lead time is needed. Currently, there has been a trend for Microsoft to apologise for not giving enough notice when posting on the Message Center. Can this be avoided here? Is good to see announcements here on the blog of course but changes like this require a lot of promotion. I hope we see this widely. Thanks

Hi John


The reason we haven't given a timeline for when we will completely stop support for the product is because we are still working on it. We understand that we haven't given our customers enough lead time in the past, but we will definitely take that into account with our future announcements. I've also updated the blog to include the timeline for the transition process. We will be sending out a Message Center post to improve the visibility of this announcement. Thanks for your feedback.

Super Contributor
Hi Mohammad, Thank you for your reply and the timeline clarification. It's appreciated.

Good move. They just weren't that useful.

Frequent Visitor

As the admin, how can I permanently remove Site Mailboxes from users outlook? 


Hi Sherry


As an admin you can remove the underlying mailbox using the PowerShell command Remove-Mailbox. Once you do this the mailbox will be removed and emails sent to it will NDR. The users will still see the site mailbox option on their respective clients but trying to fetch its contents will result in errors. The SharePoint site owner will have to manually uninstall the site mailbox app from the SharePoint site.

Occasional Visitor

When will there be a migration tool for the site Mailboxes?  Is there a command that I can run to see which site Mailboxes have content and which mail boxes do not have content so I can start removing the ones with no Content...  Our users used this feature pretty often. 



Hi James


You will soon be able to "groupify" the site so that the SharePoint site will be attached with an Office 365 group. Watch this video from the recent Ignite session regarding this. We are working on providing a way to migrate content from the site mailbox to the group. 


You can use the Get-SiteMailbox PowerShell command to get a list of all the site mailboxes in your tenant. You can pipe the output of this command to Get-MailboxStatistics to get the mailbox stats. The "TotalItemSize" and "LastLogonTime" properties will be of interest to you. Once you've identified the site mailboxes you want to delete, use the Remove-Mailbox command.