Outlook gives you two different ways to take back an email: Undo Send and Recall. They sound similar, but they work in completely different ways. Undo Send is a short window — usually 5 to 30 seconds — right after you click Send, where the message hasn’t actually left your outbox yet. Recall is a request sent to the recipient’s mailbox after the message has been delivered, asking the server to pull it back.

Here’s how to set up Undo Send in every version of Outlook, plus the workaround if you’re stuck on classic Outlook for Windows.

---

1. Outlook on the Web

Outlook on the web has had Undo Send since 2018, but Microsoft expanded the maximum delay to 30 seconds in 2024. The default is 10 seconds.

Enable and configure Undo Send

1. Open outlook.office.com and sign in.
2. Click the Settings gear icon in the top-right corner.
3. Select Mail > Compose and reply.
4. Scroll down to the Undo send section.
5. Drag the slider to your preferred cancellation window: 5, 10, 15, 20, or 30 seconds.
6. Click Save.

Use Undo Send

1. Compose and send an email as normal.
2. Watch the bottom of the screen — a toast notification appears that says Sending… Undo.
3. Click Undo before the timer runs out.
4. The message reopens as a draft. Edit it, discard it, or send it again.

Note: While the Undo Send timer is counting down, the email has not actually been sent yet. Outlook is just delaying the handoff to the mail server. This is why it’s nearly 100% reliable — unlike Recall, which depends on the recipient’s mail client.

---

2. New Outlook for Windows and Mac

The new Outlook desktop app uses the same Settings UI as Outlook on the web, so the steps are nearly identical.

Enable and configure Undo Send

1. Open the new Outlook desktop app.
2. Click the Settings gear in the top-right corner.
3. Go to Mail > Compose and reply.
4. Find the Undo send section.
5. Choose a delay between 5 and 30 seconds using the slider.
6. Click Save.

Use Undo Send

1. Send an email.
2. A toast notification appears at the bottom of the window: Message sent. Undo.
3. Click Undo within the configured window.
4. The email reopens in a compose window. You can edit it and re-send, or close it to discard.

Tip: If you’re a fast typer who frequently catches mistakes right after hitting Send, set the slider to the maximum 30 seconds. The cost is minimal — your email simply takes 30 extra seconds to reach the recipient.

---

3. Classic Outlook for Windows (No Undo Send)

Here’s the catch: classic Outlook for Windows does not have an Undo Send feature. Microsoft never built one for the legacy desktop client. If you’re still on classic Outlook (the version with the traditional ribbon and File menu), you have two options: use Recall for messages already sent, or set up a delay-send rule to mimic Undo Send for future messages.

Option A: Recall a sent message

Recall is not the same as Undo Send. The message has already been delivered to the recipient’s inbox — Recall sends a follow-up request asking Exchange to remove it.

1. Go to the Sent Items folder.
2. Double-click the message you want to recall to open it in its own window.
3. On the Message tab, click the three-dot menu (More commands).
4. Select Recall This Message.
5. Choose either:
   • Delete unread copies of this message, or
   • Delete unread copies and replace with a new message.
6. Optionally check Tell me if recall succeeds or fails for each recipient.
7. Click OK.

Recall only works when:

• Both you and the recipient are on Microsoft 365 or Exchange in the same organization.
• The recipient hasn’t opened the message yet.
• The recipient’s mailbox is configured to honor recall requests (most are by default).

If the recipient uses Gmail, Yahoo, or any non-Exchange mail server, Recall will fail. See our full guide on how to recall an email in Outlook for the details.

Option B: Set up a delay-send rule (mimics Undo Send)

This is the closest you can get to Undo Send in classic Outlook. The rule holds every outgoing message in the Outbox for a set number of minutes, giving you a window to drag it back to Drafts.

1. In classic Outlook, go to File > Manage Rules & Alerts.
2. Click New Rule.
3. Under Start from a blank rule, select Apply rule on messages I send, then click Next.
4. Leave the conditions blank (a dialog will warn you the rule applies to every message — click Yes).
5. Click Next again.
6. Under Step 1: Select action(s), check defer delivery by a number of minutes.
7. In Step 2, click the underlined a number of link.
8. Enter a delay between 1 and 120 minutes, then click OK.
9. Click Next, Next, name the rule (e.g., “Delay all sent mail by 1 minute”), and click Finish.

To cancel a message, open the Outbox before the timer expires and drag the message into Drafts — or right-click and select Move > Drafts.

Note: The delay-send rule only fires when classic Outlook is running and connected. If you close Outlook before the timer expires, the message will sit in the Outbox until you reopen the app.

For a deeper dive into delay-send rules, see how to delay sending email in Outlook.

---

4. Outlook Mobile (iOS and Android)

Outlook for iOS and Android adopted Undo Send in 2023, with a fixed window — you can’t change the duration.

Use Undo Send on mobile

1. Compose and tap Send.
2. A banner appears at the bottom of the screen: Sending… Undo.
3. Tap Undo within roughly 5 seconds.
4. The message returns to your draft view.

There is no setting to extend the mobile window. If 5 seconds isn’t long enough, your only option is to compose drafts in mobile and send them later from the desktop or web client where you control the delay.

---

Undo Send vs. Delay Send vs. Recall

These three features get confused all the time. Here’s the difference at a glance.

Feature	When it acts	How it works	Reliability
Undo Send	Before the message leaves your client (5-30 sec window)	Holds the message locally; clicking Undo reopens it as a draft	Nearly 100% — message hasn’t actually been sent
Delay Send (rule)	Before the message leaves your client (1-120 min window)	Outbox holds the message; you drag it to Drafts to cancel	High — but only if Outlook stays running
Recall	After the message has been delivered	Sends a follow-up request asking Exchange to delete the unread copy	Low — only works in same Exchange org, and only if unread

If you have a choice, Undo Send is always the right tool for “I made a mistake, give me a few seconds to fix it.” Recall is a last resort.

---

Quick Reference

Version	Undo Send available?	Max delay	Where to configure
Outlook on the web	Yes	30 seconds	Settings > Mail > Compose and reply
New Outlook (Windows/Mac)	Yes	30 seconds	Settings > Mail > Compose and reply
Classic Outlook for Windows	No	N/A	Use delay-send rule or Recall
Outlook for iOS/Android	Yes	~5 seconds (fixed)	Always on, no setting

---

Common Issues

The Undo button disappears too fast. Increase the slider to 30 seconds in Settings > Mail > Compose and reply.

I missed the Undo window. If the message has already been sent, your only option is Recall (Exchange-to-Exchange only) or sending a follow-up apology. There’s no second chance.

Undo Send isn’t in my settings. Make sure you’re using Outlook on the web or the new Outlook desktop app. Classic Outlook doesn’t have it. If you’re on the new Outlook and still don’t see it, your admin may have disabled the option via tenant policy.

My emails take 30 seconds to send now. That’s by design — the delay is what makes Undo Send work. If you find it disruptive, lower the slider to 5 or 10 seconds.

---

Stop Catching Mistakes After You Hit Send

Undo Send is a safety net. If you’d rather have an AI assistant draft and review your emails before they go out, Carly connects to Outlook and 200+ other apps and handles your inbox the way you’d want a chief of staff to handle it — for $35/month.

More on Outlook: How to recall an email in Outlook · How to delay sending email in Outlook · How to schedule an email in Outlook · How to create rules in Outlook · How to use Quick Steps in Outlook · How to add a signature in Outlook · How to create an email template in Outlook · How to fix Outlook search not working

Related Articles

Guides

How to Forward a Meeting in Outlook (2026 Guide)

Apr 30, 2026

Guides

How to Print Emails in Outlook (2026 Guide)

Apr 30, 2026

Guides

How to Save Attachments in Outlook (Every Version, 2026)

Apr 30, 2026