Microsoft Retires Another Early Copilot Feature

Launched with gusto in July 2025, Microsoft is retiring the Copilot-powered Prioritize My Inbox feature. According to message center notification MC1519861 (updated 22 October 2026), the withdrawal process started on October 26, 2026, and is due to complete by the end of March 2027. Withdrawal means that the Prioritize feature will disappear from menus in Outlook clients without user or administrator intervention. Figure 1 shows the option in Outlook classic. The snippets for messages include an upward-facing arrow, meaning that Copilot deems these messages to be high priority.

Microsoft says that “This change allows us to simplify the Outlook Copilot experience and focus our ongoing investments.” Indeed.

The change only affects users who currently have access to Copilot Prioritize. In practice, this means users with Microsoft 365 Copilot licenses.

A History of Automated Inbox Filtering

Microsoft has a history of attempting to put manners on the Inbox by applying automated filtering to highlight important new email. Originally shown at the revamped Microsoft Exchange Conference in late 2012, the first iteration was Clutter, a method to detect unwanted or unimportant email and move these items to a Clutter folder. The software learned from user behavior and, later, user-configured instructions to improve its understanding of which messages were important.

Looking back now at a time when AI is everywhere, the machine learning techniques used in Clutter seem so archaic. But at the time, Clutter seemed a little like black magic, mostly because no one could reliably predict what would end up in the Clutter folder. Microsoft eventually shipped Clutter for OWA in late 2014 and continued to tweak the software for a couple of years thereafter.

Focused Inbox

Around the same time, Microsoft bought the Acompli email client to rescue their mobile email story. OWA for Devices, a wrapper to run OWA in a browser on mobile devices, was going nowhere fast, and customers were voting with their wallets to buy and run Acompli. Microsoft rebranded Acompli to become Outlook for IOS and Android in early 2015. The Focused Inbox was the star feature of the new client. Eventually Focused Inbox reached all Outlook clients with Outlook desktop being the last to receive the feature in 2017. It’s a marquee feature that helped to make Outlook Mobile the standard mobile client for Exchange Online.

Many people love Outlook’s ability to divide the Inbox into Focused and Other by placing new messages into either view. A view is a filter for a folder. In this case, the views are based on a message property that tells Outlook in which view a message should appear. It takes time to train Focused Inbox by patiently moving misclassified messages between Focused and Other. After many years of training, my Focused Inbox is pretty good at maintaining the two views.

However, other people, like the esteemed Mary-Jo Foley, hate Focused Inbox to this day because it is a black box like Clutter.

The Real Way for AI to Prioritize My Inbox

Focused Inbox still persists and can be used alongside Copilot’s Prioritize My Inbox feature. The problem of users not knowing what happens behind the scenes persists. Copilot prioritization therefore seemed like more of the same, and overlapping solutions make obvious candidates for rationalization.

Microsoft seems to be rationalizing the first wave of Copilot integrations with the Office apps to create a more coherent experience. Clearing the decks to concentrate on higher-impact and more flexible solutions might have doomed a single-purpose feature like Prioritize My Inbox. Microsoft has certainly done plenty of work to smooth the integration of Copilot Chat into the apps. There’s also Copilot Cowork to consider, or even Autopilot (aka Microsoft Scout), both of which point toward assistants that can perform tasks on behalf of users.

Prioritizing an inbox by extracting important email seems like an ideal task for an AI assistant, especially if users can describe what matters to them in natural language and let the assistant apply those instructions as new messages arrive. Inevitably, “important” can often be boiled down to email from anyone above you in the organizational hierarchy. But who knows? The AI might disagree.

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