In your apps · 2 min

Catch up on a long email thread in Outlook

Outlook, Summary by Copilot

Short answer: Open the conversation in Outlook and select Summary by Copilot (or Summarize) at the top. The summary appears above the thread with numbered citations that jump to each email. In new Outlook you can also summarize Word, PowerPoint or PDF attachments.

Last checked against Microsoft docs: Oct 21, 2026

You've seen people paste a long email chain into ChatGPT for a summary. Here's how in Copilot: open the thread in Outlook and select Summarize. No copy and paste.

A common situation (composite)

My boss adds me with "see below, can you handle?"
Below is three weeks of replies.
I need to know what's being asked of me.

What you get

Data: one email thread in your primary mailbox.
Does: summarizes the key points.
Output: a summary with citations to each email.
How often: any long thread.

Before you start

Needs: Copilot in Outlook with a work account. Not sure what you have? Start here.
Where: Outlook, Summary by Copilot.
Access: Copilot only uses content you already have permission to open. Use only information your company allows in Copilot.

The steps

Open the conversation in Outlook.
Select Summary by Copilot or Summarize at the top.
Click the numbered citations to check key points.
If you need to reply, use Draft with Copilot or the sales follow-up guide.

Copy this prompt

From this thread: what is being asked of me, by whom, and by when? What's already been decided? What's still open?

(Prompt from stuckwithcopilot.com/guides/outlook-thread-catch-up/)

Data tip: use this with your work Copilot, and leave out passwords, payment details and anything your company marks restricted.

What a good result looks like

Click the citation for anything you'll act on.

If a feature is missing

Copilot in Outlook works on your primary mailbox only, not shared, group or archive mailboxes, and not on S/MIME encrypted mail.

Make it smarter

Keep a short "What it got wrong" note. Paste it above the prompt next time, like "Don't invent dates".

Not sure what to ask? Copy the quick note for your Copilot admin.

When the thread is a complaint

Summaries matter most when a customer is unhappy and several people have already replied. Get the facts sorted before anyone sends another answer.

Summarize first: use Summary by Copilot, then ask what's been promised.
Find contradictions: ask where people on your side said different things.
Replying: use the upset customer guide for the reply.

Prompt

From this thread: what is the customer upset about, what do they want, and what has anyone on our side promised, with dates? Point out anything our replies say that contradicts each other.

(Prompt from stuckwithcopilot.com/guides/outlook-thread-catch-up/)

Make it better

Run this next, in the same chat.

List the three questions I need answered by our team before I reply, and who should answer each one.

(Prompt from stuckwithcopilot.com/guides/outlook-thread-catch-up/)

Data tip: use this with your work Copilot, and leave out passwords, payment details and anything your company marks restricted.

Questions people ask

Catch up on a long email thread in Outlook?

Open the conversation in Outlook and select Summary by Copilot (or Summarize) at the top. The summary appears above the thread with numbered citations that jump to each email. In new Outlook you can also summarize Word, PowerPoint or PDF attachments.

What do I need for this?

Copilot in Outlook with a work account. Copilot in Outlook works on your primary mailbox only, not shared, group or archive mailboxes, and not on S/MIME encrypted mail.

Why don't I see Summary by Copilot?

Your Outlook version or license may not include it yet. Paste the thread into Copilot Chat instead.

Next step

Try it once, then make it yours.

Run the prompt on one real task this week. Then pick your next workflow.

See the workflow library ↗

Cite or share this guide

Catch up on a long email thread in Outlook. Stuck with Copilot. https://stuckwithcopilot.com/guides/outlook-thread-catch-up/ Last checked Oct 21, 2026.

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Official references

Last checked against Microsoft docs: Oct 21, 2026.