You need to quickly understand a long email thread in Outlook without reading every message. Microsoft Copilot can generate a summary of the conversation, highlighting key points and decisions. This feature saves time when you join a thread late or need to catch up on a busy inbox. In this article, you will learn how to activate the Copilot summary feature in Outlook, what prerequisites are required, and how to handle common issues.
Key Takeaways: Using Copilot to Summarize Email Threads
- Copilot icon in the Outlook ribbon: Click the Copilot icon while viewing a thread to see the Summarize option.
- Microsoft 365 Copilot license: Required for the summary feature to appear in Outlook.
- Thread selection rules: Copilot summarizes only the currently selected thread, not your entire mailbox.
How Copilot Summarizes Email Threads
Copilot uses the Microsoft Graph to read the content of the email thread you are viewing. It identifies the main topic, lists key points from each message, and notes any action items or decisions. The summary appears in a pane to the right of your message list. You do not need to install any add-in or plugin. The feature is built into Outlook for Microsoft 365.
Before you can use the summary feature, your organization must have a Microsoft 365 Copilot license assigned to your account. The license is a per-user subscription that enables Copilot across Word, Excel, PowerPoint, and Outlook. If you do not see the Copilot icon in Outlook, your administrator may not have enabled the feature or you may not have the correct license.
The summary works only on email threads stored in your Exchange Online mailbox. It does not work on emails from external accounts such as Gmail or Yahoo. The thread must contain at least two messages for Copilot to generate a meaningful summary.
Steps to Generate a Summary in Outlook
Follow these steps to summarize an email thread using Copilot in Outlook.
- Open Outlook and select a thread
Launch Outlook on your desktop or access Outlook on the web. From your inbox, click any email thread that contains multiple messages. The thread expands to show all messages in the reading pane. - Locate the Copilot icon in the ribbon
At the top of the Outlook window, find the Copilot icon. It looks like a small sparkle or a chat bubble with a sparkle. The icon is located in the Home tab on the desktop app or near the top-right area on Outlook web. - Click the Copilot icon and select Summarize
Click the Copilot icon. A dropdown menu appears. Choose the option labeled Summarize or Summarize by Copilot. If you do not see this option, the thread may not meet the minimum requirements or your license may be inactive. - Review the summary in the Copilot pane
A pane opens on the right side of the Outlook window. Copilot displays a summary of the thread. The summary includes the main topic, key points from each message, and any action items. You can copy the text from this pane or close it by clicking the X in the corner. - Refine the summary if needed
At the bottom of the Copilot pane, you can type a follow-up question. For example, type What decisions were made? or List all action items. Copilot updates the summary based on your request.
If Copilot Does Not Show the Summarize Option
Copilot icon is missing from the ribbon
The Copilot icon does not appear if your Microsoft 365 license does not include Copilot. Contact your IT administrator to confirm that you have a Microsoft 365 Copilot license assigned. The license name is Microsoft 365 Copilot or Copilot for Microsoft 365. Without this license, the icon is not visible.
Summarize option is grayed out
The Summarize option is disabled when you select a single email message instead of a thread. Click any email that is part of a thread with at least two messages. The option also stays gray if your mailbox is hosted on an on-premises Exchange server. Copilot requires Exchange Online.
Summary is blank or shows an error
A blank summary can occur if the thread contains only images or attachments with no text. Copilot reads only the text body of each email. If the thread is very long, Copilot may time out. Try selecting a shorter subset of the thread by clicking the first and last messages while holding Ctrl, then click Summarize.
| Item | Outlook Desktop | Outlook on the Web |
|---|---|---|
| Copilot icon location | Home tab, far right | Top toolbar, near search bar |
| Summary pane behavior | Opens as a side panel | Opens as a side panel |
| Follow-up question support | Yes, via text input | Yes, via text input |
| Minimum thread messages | 2 | 2 |
You can now use Copilot to summarize any email thread in Outlook. This feature reduces the time you spend reading long email conversations. For best results, use the follow-up question field to ask for specific details such as deadlines or assigned tasks. If you work with shared mailboxes, note that Copilot summarizes only your own mailbox and not group mailboxes by default.