Microsoft Changes Storage Location for Email Sent to Teams Channels

Unexplained and Unannounced Change Affects Tenant Processing

The ability to send email to a Teams channel has existed since the earliest days of the product. If Email integration is turned on (the default) for Teams (in the Teams settings section under Org-wide settings in the Teams admin center), team members can retrieve an email address for a channel using the Get email address option (Figure 1). If the address doesn’t already exist, Teams creates one in the form Channel display name <guid.domain@region.teams.ms>. Guid is a unique identifier and region is the datacenter region the tenant belongs to.

Getting the email address for a Teams channel
Figure 3: Getting the email address for a Teams channel

The email address is a tad strange, you can’t change it, and any team member can remove and replace the address, but the mechanism works to get email into Teams. Any message sent to the address is picked up by a connector and posted as a new conversation in the target channel. Team members can then reply to the conversation as they wish (replies do not go back to the original sender).

All in all, sending email to a channel is a simple and effective way of taking messages which arrive at any mailbox and share information with Teams. Outlook’s Share to Teams option is a more elegant option if you have a supported client, but it doesn’t offer the flexibility of an email address.

Guest Account for a Teams Channel

I often create a guest account or mail contact using the email address for a Teams channel. This technique allows me to include the channel as a member of Microsoft 365 groups (guest account) or distribution lists (mail contact), and be visible in the GAL. Once available in the GAL (Figure 2), anyone in the tenant can send or forward messages to the channel as easily as addressing any other recipient. This is an example of the flexibility of the channel email address.

Teams channel address listed as a mail contact in the GAL
Figure 2: Teams channel address listed as a mail contact in the GAL

Teams Channel Email and SharePoint Online

When email arrives for a channel, Teams captures a copy in the SharePoint team site belonging to the team. Each channel has its own folder, and if messages arrive in the channel, they go into the Email Messages folder under the channel folder.

That is, until February 5 when Microsoft changed how delivery works. Instead of creating copies in the Email Messages folder, a new folder called EmailMessages_2_2021 appeared in the channel folder (Figure 3). New messages received since are in this folder. The speculation is that Teams will use a new folder for the messages delivered each month.

The EmailMessages_2_2021 folder appears in Teams
Figure 3: The EmailMessages_2_2021 folder appears in Teams

Breaking Flows

On the surface, there’s nothing bad here. Microsoft had some reason to change how SharePoint stores email delivered to Teams. It seems like a sensible idea to use separate month-based folders instead of stuffing everything into one big folder. There doesn’t seem to be a technical reason for the change as the documentation for SharePoint Online limits doesn’t mention anything that seems to be related, with the only mention that when a folder contains more than 100,000 items, you can’t break permissions inheritance.

But making an unannounced change without warning can have unexpected consequences for service users. In this case, users noted that Power Automate flows failed because messages went to the new folder instead of the expected folder. The workaround is to create yet another flow to trigger when .eml (message) files appear in the document library and create a copy where the original flow expects it to be. Although this works, it is clunky and shouldn’t be necessary. And what about the people who don’t realize yet that a change has happened?

Microsoft knows about the problem. However, there’s no word yet how they plan to address the issue. When we know, we’ll publish an update here.


Changes like this are the bread and butter of the Office 365 for IT Pros writing team. We see similar updates come along every month and process them as updates to book chapters. Once we get to the bottom of this development, we’ll update Chapter 12. Stay updated by subscribing to Office 365 for IT Pros – the only book about Office 365 tenant management republished monthly.

4 Replies to “Microsoft Changes Storage Location for Email Sent to Teams Channels”

  1. The format of the folder name could certainly be better. ISO representation of date would be preferred e.g. “EmailMessages_2021-02”. Second choice would be “EmailMessages_02_2021” so folders would at least sort properly. Sheesh.

  2. it would be better if those folders were created inside a parent folder. I don’t really like this proliferation of folders

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