Site mailbox or public folders?

Microsoft messaging and online collaboration platforms keep gaining new features with almost every new release. Many of these enhancements are workflow innovations proposed exclusively by Microsoft, which are supposed to attract new users to their flagship enterprise products and show their advantage over competition, e.g. over Google. A good example of such invention are site mailboxes introduced for the first time in Exchange Server 2013 back in 2012.

As it often happens with new ideas, the big question back then was: Will this feature fit into real business world and will real users find a place for a new tool in real workflow and project management? As Exchange Server 2013 keeps growing well with SP1 released just a few weeks ago, it is a good moment to check whether site mailboxes adapted well in organizations running Exchange 2013 or Office 365. Let’s consider their strengths and weaknesses then.

Bringing Exchange Server and SharePoint together

What are site mailboxes actually? What is the difference between them and public folders? What is the added value a company will get if they decide to deploy this feature in their workflow?

In theory site mailboxes were designed to combine SharePoint’s resource sharing features with emails and conversations processed by Exchange. In other words, this feature allows users to access and update the document and calendar archive of SharePoint 2013 without the need of leaving Outlook. It also binds documents and resources stored in Team Sites with conversations team members are having. Documents and other project resources are no longer left without context. Since a site mailbox behaves like a normal mailbox, users can send emails to it and every team member is read its contents.

Every document from your Team Site is now easily accessible from Outlook 2013:

Document archive in site mailboxes

The same document archive is also displayed on the Team Site in SharePoint 2013:

Document archive in site mailboxes

Placing a mail attachment in the Team Site document repository is as simple as drag’n’droping it into one of the Outlook folders:

Drag and drop attachments to site mailbox

The idea of a site mailbox is close to public mailboxes, e.g. those in Exchange public folders. However, a classic public mailbox on Exchange lacks the ability of accessing SharePoint. You can’t synchronize SharePoint documents with Outlook simply by creating a public folder on Exchange.

No sync between Exchange and Sharepoint

How to configure site mailboxes?

This is where tough administrative work begins. Although the functionalities described above sound pretty simple, the configuration of site mailboxes in an on-site environment is complex. Needless to say you need to be running Exchange 2013 and SharePoint 2013 on your servers. You also have to establish a trust relationship between them and let them communicate over SSL. Most of the configuration however is done on the SharePoint side. This Microsoft article describes the setup process in detail.

Things get a bit easier, if you use Office 365, where site mailboxes are already enabled and configured. The only thing that needs to be done is, creating a site mailbox for the given Team Site by clicking on one of the options in SharePoint Online administration panel:

Creation of a site mailbox

Note! Only one mailbox per site is allowed.

As long as the site mailbox is created in SharePoint, users should be able to see them in Outlook 2013 after restarting their mail clients. Sometimes, however, it may take some time until settings between Exchange and SharePoint synchronize, it takes longer when your environment is based in the Cloud (Office 365).

Where’s the catch?

The biggest drawback of site mailboxes, which often disqualifies the usage of their full potential in organizations is that they require Exchange, SharePoint and Outlook, all in the 2013 versions. Although you can imagine upgrading all your servers to the latest versions of Exchange and SharePoint, getting all your client machines running Outlook 2013 can become a big problem. Especially in larger companies where a lot of users still use Windows XP and Outlook 2003.

Deciding on Office 365 makes it a lot simpler, but still you will need Office 2013 on all workstations that need to connect to site mailboxes. What’s more, I personally experienced some serious lags in Outlook synchronization. Sometimes it took a couple of hours until the changes were replicated to the mail client.


Although there’s no doubt that site mailboxes brought great new value to Exchange Server’s and SharePoint’s collaboration features, it is still not clear if they become commonly used by organizations. Because of the fact that many companies are still expected not to upgrade their software infrastructure to the latest 2013 versions, it still may take some time until we will be able to find out if this new feature adapts in real work scenarios. It is also not clear if the concept of site mailboxes will continue to grow in its current shape. This year’s MEC announcements showed that the idea of social collaboration is constantly being developed at Microsoft and site mailboxes may soon become a part of a wider collaboration concept called Groups. Will this plan become a reality soon? Future will tell.

Suggested reading

Speed up your migration to Exchange 2013 and start using site mailboxes
CodeTwo Exchange Sync: Exchange public folders in mobile devices

Tools for Exchange Server

2 thoughts on “Site mailbox or public folders?

  1. Here is a new update to an old post, we are heading down the site mailbox road with Exchange, SharePoint and Office 2016. This is probably as close as Microsoft has come to convincing people to utilze SharePoint in liu of Public Folders.

    The 1st issue we just ran into? The site mailboxes don’t display in Office 2016 Home and Business, you have to have Professional or above aparently. I haven’t yet found a work-around let alone any other articles that bring this fact to light. If you have a lot of users with Home and Business instead of Professional, expect the same issue.

  2. Hi Adam,

    Nice article you have there. I would like to add something about site mailboxes that it seems no one is yet to mention( or I am just missing out on information.
    Through a pratical experience I have learnt even having Exchange 2013, SharePoint 2013 and Outlook 2013 doesn’t necessary support the Site Mailbox functionality. I manage an accounts domain which also host SharePoint 2013. In order to enable the functionality site mailboxes, an IT service provider adviced that a resource domain be setup and Exchange 2013 be installed.With Trust established between both domains and linked mailboxes for each user setup I have successfully enabled user access to site mailboxes within SharePoint. On the other hand, the critical functionality of accessing sitemails and documents from within outlook does not work(even with outlook 2013 installed for users).My only explaination for this is the fact that accessing a site mailbox from a user with an Exchange 2010 mailbox in outlook 2013 isn’t supported. For me it’s just a furstrating case that probably still needs development.

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