Clutter in Office 365 (Part 1)

If you would like to read the next part in this article series please go to Clutter in Office 365 (Part 2).


According to the Oxford Dictionaries, clutter can be defined as “a collection of things lying about an untidy mass”.

Figure 1: Definition of clutter

Now think about email for a while, and think about your own inbox. Does it sound familiar? At this time, I could throw in a handful of studies about how much time we spend (waste?) reading, writing and managing email, but it’s not really necessary because we’ll easily recognize the hard facts from the myriad of statistics and infographics available on the Intranet.

Email is not a bad thing (in case you start wondering about its usefulness), in fact I think of it as one of the best tools from the Internet world and although many tried to reinvent it along the years, either by adding social features or by making it more real time, (electronic) written communication will always be a privileged means for doing business or catching up with friends.

Now, enter the frustration about the tons of messages that flood our Inbox and the lack of human capacity to process them all, because we do feel compelled to read and reply those important bits of information. If they weren’t important, they would be discarded as junk, right? This poses the question, are all the messages created equal? I don’t think so, neither does Microsoft, that’s why Clutter was created, to draw a line between what’s really important for us and what’s not so critical and urgent, but that can’t be categorized as junk email.

Clutter uses machine learning to help you focus on the most important messages in your inbox by moving lower priority messages out of your way and into a separate mail folder. Ultimately, Clutter removes distractions so you can focus on what matters most.

Email is not a drama, it doesn’t have to be, but clutter can be… If it wasn’t, there wouldn’t be a film about it!

Figure 2: Clutter, the movie (not about the Office 365 feature!)

Overview and history

Clutter was officially introduced in Office 365 in November 2014, although it had been in preview since March 2014 (announced at the Sharepoint Conference 2014). Clutter was one of the first practical applications of the then new Office Graph. At the core of its genesis was the desire to come up with a simple way to deal with the high volume of email messages, without the need to manage lots of different inbox rules that separate and classify messages according to its content.

What if we had an intelligent inbox that could learn from our actions when working with email, knowing who are the persons from whom we reply their messages very quickly and the others who we mostly ignore? Would it be useful to have that same intelligent system inspecting the content of the messages we value the most and then, as it learns, presenting those messages to us in a cleaner inbox?

Well, that’s exactly what Clutter does. It has zero configuration and it leverages Office Graph’s sophisticated machine learning, getting better over time with continuous learning as you treat email messages and looking for patterns behind those behaviors. You can proactively train Clutter by marking items as Clutter or simply move the items to the Clutter folder. If you find items in your Clutter folder that shouldn’t be there, train Clutter by moving the message back to your inbox. Clutter respects your existing email rules, so if you have created rules to organize your email those rules continue to be applied and Clutter won’t act on those messages.

The Clutter experience is personalized to each individual. The information Clutter learns from each user’s actions is only applied to that user and are not shared with anyone else. Clutter is best suited and most effective for those of us who tend to pile up messages in our inboxes.

Figure 3: Mailbox with Clutter enabled

Clutter is an Office 365 feature (it doesn’t apply to Exchange Server 2016 or any previous version) and will become on by default for all users in tenants where the feature is available. Each person controls whether to turn Clutter on or off from the Outlook on the web (aka OWA) options menu. Clutter begins taking actions once it has sufficiently learned your work style and can confidently begin working for you. If you later find Clutter isn’t for you, it can be turned off at any time.

The Clutter folder allows you to take advantage of the feature across many email clients including Outlook, Outlook on the web, OWA for devices, or EAS connected devices. Clutter continuously learns from your actions across these clients. Regardless of the client, the messages moved to the Clutter folder are out of your inbox view, yet readily accessible.

Users can check their Clutter folder as frequently or infrequently as they like. Thanks to Clutter, the inbox should only contain the email messages that matter, allowing them to focus on what’s important and get the work done in an efficient way.

The science behind clutter

Clutter leverages machine-based learning, powered by Office Graph in Office 365. The “learning part” is based on Bayesian Probit Regression developed by Microsoft Research using Infer.Net. A time-based assistant periodically processes new information and everything learned is securely stored in each user’s mailbox.

Figure 4: Bayesian Probit Regression Model

Clutter and junk email are both filtered out before they reach your Inbox. Junk email is evaluated and filtered first, then Outlook processes the rules (if you have set up any). Next, Clutter analyzes the remaining messages and filters out the types of messages that you usually ignore or don’t respond to, based on your past behavior.

Messages from certain people will never be identified as clutter:

  • You
  • Anyone in your management chain
  • Your direct reports

Clutter looks at various aspects of messages to understand what you don’t typically read, for example:

  • The sender
  • Whether you’ve participated in the conversation
  • If you’re the only recipient
  • The importance

As your reading habits change, Clutter learns and adapts.

If you want to explore a little bit more the insides of Clutter, Glen Scales has built an Outlook form that expose 2 MAPI properties used by Clutter: ClutterProbability and ClutterThreshold.

Working with Clutter

In order to start using Clutter, we need to turn it on in Outlook on the web (OWA).

  1. Sign in to Outlook Web App. At the top left corner of the page, select the App launcher icon, and then select Mail (Figure 5).

Figure 5: App launcher

  1. On the top right corner of the page, go to Settings > Options > Mail > Automatic processing > Clutter. Select Separate items identified as Clutter, then Save (Figure 6). It might take Clutter a few days to fully adapt to your preference, as the system records your choices and uses the information to identify similar messages in the future.

Figure 6: Clutter settings

  1. You can turn Clutter off anytime by deselecting Separate items identified as Clutter. The Clutter folder remains in Outlook after you turn off the Clutter feature.
  2. You can help Clutter learn your choices faster: if you see a low priority email in your Inbox, right-click the message and choose Move to Clutter (Figure 7 and Figure 8), or drag the email from your Inbox and drop it into the Clutter folder.

7: Move to Clutter in OWA

8: Move to Clutter in Outlook

  1. If you see a message that was sent to Clutter by mistake, right-click the message and choose Move to inbox (Figure 9 and Figure 10), or drag the email from the Clutter folder and drop it in your Inbox. The system will also recognize that it made a mistake, and will use this signal to adjust the model accordingly.

9: Move to inbox in OWA

10: Move to inbox in Outlook

  1. Items in the Clutter folder display slightly different than those in the Inbox; specifically, there are fewer lines of information and the messages have shortcut icons for Clutter folder actions (Figure 11).

11: Messages in Clutter folder

  1. If you have Outlook 2016 for Windows, you can right-click the Clutter folder and choose Manage Clutter (Figure 12). You’ll be directed to Outlook on the web to manage your Clutter options.

12: Manage Clutter

Clutter notifications

Clutter is designed to work across a broad range of email applications, browsers and devices. To provide a consistent notification experience, system notifications are delivered via inbox messages to inform people how to use Clutter. Right after enabling the feature, you’ll get a welcome message, as depicted in Figure 13.

13: Clutter welcome message

During the first three weeks of Clutter usage, you may get the following notification (Figure 14) to remind the user to inspect the Clutter folder and make sure that Clutter is filtering messages correctly.

14: Clutter is hard at work

Alerts are sent when new types of emails are moved to Clutter for the first time (maximum of one alert per day). The summary notification is sent once per week making it easy to know what Clutter is doing for you (Figure 15).

15: Clutter moved new messages

You can personalize these system notifications by controlling which sender display name is shown and, in the near future, by adding your custom logo to these messages. An example of the personalized notification is depicted in Figure 16.

16: Personalizing your Clutter notifications

To configure a reply-to address for Clutter notifications and change the sender display name, follow these steps:

  1. Sign in to Office 365 and go to the Office 365 admin center. Click to expand Users, then select Active Users and add a new user.
  2. In the Create a new user account dialog, enter a Display name and a User name. The display name will appear in the Sender field for all Clutter notifications sent to your users. Office 365 generates a new temporary password for the new user account. Click Create to create the account (Figure 17).

17: Create new user account

  1. Go the Exchange admin center. Click recipients, and then click mailboxes. Select the user you just created, and then edit the account. In the user account dialog, click email address, and then click the plus sign [+] to add an email address to the new user account. In the Email Address box (Figure 18), type the following: [email protected][your default domain], where [your default domain] is the domain that your organization uses.

18: new email address


  1. All Clutter notifications sent to end users in your organization will now originate from this account.
  2. You can also use PowerShell to create a shared mailbox (doesn’t consume an Office 365 license) for the same effect:

a)    New-Mailbox -Shared -Name [email protected] -DisplayName “Branding Clutter Mailbox” -Alias branding

b)    Set-Mailbox “Branding Clutter Mailbox” -EmailAddresses SMTP:[email protected], SMTP:[email protected]


There is no denying that people and organizations depend on email more than any other digital communication medium. The downside of email’s popularity is that people receive so much of it that they often experience inbox overload, leading to loss of productivity because of the necessary time to manage the high volume of messages received.

Fortunately, technology is enabling new ways of working and maybe the Clutter feature in Office 365 might be a major contribute for us to regain control of our Inbox.

If you would like to read the next part in this article series please go to Clutter in Office 365 (Part 2).

1 thought on “Clutter in Office 365 (Part 1)”

  1. Hi,

    Is there a way to turn it off for whole organization so that new account mailboxes have it disabled by default? I do not want to turn it off manually after creating the mailbox. It must be off from the start.

Leave a Comment

Your email address will not be published.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Scroll to Top