How to Summarize Email Threads in Outlook with Copilot

How do you use Copilot in Outlook to summarize a long email thread and draft the reply? In this lesson I share my screen: Summary by Copilot catches a date change buried in the thread, the citations take you to the real message, and one question turns the thread into your to-do list. Then I show what happens when you just say "write a reply" (it claims things you never did), and how to fix it by putting your decision in the prompt. In this lesson: Summary by Copilot, and how to check it with the citations One question that shows who is waiting on you, and for what What "write a reply" gets wrong The rewrite prompt: put your decision in the prompt The three parts of a good reply prompt A prompt for managers on long threads What goes wrong: mixed-up dates, plain text email, Basic licenses Prompts from this lesson (copy and try them): Who is waiting on me in this thread, and for what? Rewrite the reply: confirm [what you decided]. Thank [name] for [what they did]. Under 100 words, professional, no exclamation marks. For managers: Reply to all: [your decision]. [Who owns what]. Please confirm by [time]. Calm, under 120 words. Chapters: 0:00 Summarize a thread and write the reply 0:26 Summary by Copilot 0:55 Check the citations 1:06 The real message 1:38 Who is waiting on me? 2:07 Write a reply 2:32 What Copilot made up 2:56 Put your decision in the prompt 3:20 The new draft 3:49 Three parts of a good reply prompt 4:09 For managers 4:43 What goes wrong 5:09 Recap: three things to do today This is Lesson 8 of Copilot at Work: 30-Day Microsoft 365 Copilot Course. Watch the whole course in order:    • Copilot at Work: 30-Day Microsoft 365 Copi...   Previous lesson: Catch up on email and Teams after time off with Copilot    • How to Catch Up on Email After Vacation Wi...   Next lesson: Coaching for hard emails and Prioritize in Outlook    • How to Fix Email Tone in Outlook with Micr...   Sample work, fictional project. Tested in September 2026 with Outlook for Mac and Microsoft 365 Copilot (Premium). Independent training. Not affiliated with or endorsed by Microsoft. #MicrosoftCopilot #Outlook #Microsoft365