When you switch from Classic Outlook to the new Outlook for Windows, one of the first settings you might look for is Undo Send. In Classic Outlook, this feature is called Undo Send and is configured in the Compose Messages section of Outlook Options. In the new Outlook, the same feature exists but is named Undo Send and cancellation works differently. This article explains where to find Undo Send in the new Outlook, how to adjust the cancellation time, and what changes when you move from Classic to the new app.
The new Outlook uses a different settings interface. The classic File > Options menu is replaced with a simplified Settings panel. The Undo Send feature in new Outlook gives you a maximum of 10 seconds to cancel a sent email. If you relied on longer cancellation windows in Classic Outlook, you need to know the new limit and how to set it.
This article covers the exact steps to enable and configure Undo Send in new Outlook. It also explains limitations compared to Classic Outlook and what to do if the feature does not appear after switching.
Key Takeaways: Configuring Undo Send in New Outlook
- Settings > Mail > Compose and Reply > Undo Send: The only location to enable Undo Send and set the cancellation timer in new Outlook.
- Maximum 10 seconds for cancellation: New Outlook allows 5, 10, or no delay. Classic Outlook allowed up to 30 seconds.
- Undo banner appears at the bottom of the screen: After sending, a banner shows Undo and Sent. Click Undo within the set time to recall the message.
How Undo Send Works in New Outlook vs Classic Outlook
In Classic Outlook, Undo Send is a rule that delays sending every message by the number of seconds you set. The feature is located under File > Options > Mail > Send Messages. You can set a delay from 0 to 30 seconds. When you click Send, the message stays in the Outbox folder for the duration you specified. You can open the Outbox, double-click the message, and stop it from being sent.
In new Outlook, Undo Send works differently. The message is sent immediately to the server, but the new Outlook app shows an Undo banner at the bottom of the screen for the time you set. If you click Undo, the app sends a recall request to the server. The message is not stored in an Outbox folder. You cannot manually stop the send by opening a folder. The maximum delay in new Outlook is 10 seconds, and the minimum is 5 seconds. You can also turn the feature off entirely.
The difference in architecture means that in new Outlook, the message is technically sent before you click Undo. The recall depends on the server accepting the undo command. In Classic Outlook, the message never leaves your Outbox until the delay expires. This makes Classic Outlook more reliable for long delays. The new Outlook feature is designed for quick corrections, not for extended review.
Prerequisites for Using Undo Send in New Outlook
You must be using the new Outlook for Windows app. The feature works with Microsoft 365, Exchange, and Outlook.com accounts. It does not work with POP or IMAP accounts. You must be online when you send the message and when you click Undo. If you lose internet connection after sending, the Undo banner may not appear or the recall may fail.
Steps to Enable and Set Undo Send in New Outlook
Follow these steps to turn on Undo Send and choose your cancellation time in new Outlook.
- Open Settings in New Outlook
Click the gear icon in the top-right corner of the new Outlook window. The Settings panel opens on the right side of the screen. - Go to Mail Settings
In the Settings panel, click Mail near the top of the list. A submenu appears below Mail. - Select Compose and Reply
In the Mail submenu, click Compose and Reply. This page contains options for message formatting, replies, and sending behavior. - Find Undo Send
Scroll down the Compose and Reply page until you see Undo Send. It appears as a dropdown menu labeled Undo Send. - Set the Cancellation Timer
Click the dropdown and select one of the three options: Off, 5 seconds, or 10 seconds. The default in new Outlook is Off. Select 10 seconds for the maximum cancellation window. - Close Settings
Click the X in the top-right corner of the Settings panel. Your change saves automatically. No restart is required.
To test the feature, compose a test email and send it to yourself. After clicking Send, look at the bottom of the Outlook window. A banner appears with the text Undo on the left and Sent on the right. Click Undo within the time you set. The message is recalled and a confirmation banner appears. If you do not click Undo, the banner disappears after the timer expires.
If Undo Send Does Not Appear in New Outlook
Some users report that the Undo Send setting is missing or the banner does not appear after sending. The causes and fixes depend on your account type and Outlook version.
Undo Send Option Is Grayed Out or Missing
This usually happens when you are using a POP or IMAP account. Undo Send in new Outlook requires an Exchange, Microsoft 365, or Outlook.com account. To check your account type, go to Settings > Accounts > Email accounts. If the account type says POP or IMAP, Undo Send is not available. You can add an Outlook.com or Microsoft 365 account to get the feature.
Undo Banner Does Not Show After Sending
If you enabled Undo Send but the banner does not appear, the most common cause is that you set the timer to Off. Open Settings > Mail > Compose and Reply and verify that Undo Send is set to 5 seconds or 10 seconds, not Off. Also check that you are using the new Outlook app, not Classic Outlook. The new Outlook title bar shows Outlook with a simple logo, not the Classic Outlook icon with a letter icon on a blue background.
Undo Click Does Not Recall the Message
If you click Undo but the message still arrives in the recipient’s inbox, the recall failed. This can happen if you lose internet connection between sending and clicking Undo. It can also happen if the recipient uses a different email system that does not support recall. In new Outlook, the undo feature sends a server-side recall command. If the recipient’s server rejects the recall, the message stays delivered. There is no local Outbox to intercept the message before it leaves your device.
Cached Exchange Mode vs Online Mode: Undo Send Behavior
| Item | Classic Outlook | New Outlook |
|---|---|---|
| Send delay method | Message stays in Outbox folder | Message sent immediately, recall requested |
| Maximum delay | 30 seconds | 10 seconds |
| Account support | All account types | Exchange, Microsoft 365, Outlook.com only |
| Manual cancellation | Open Outbox, delete message | Click Undo banner only |
| Recall reliability | High — message never left client | Depends on server accepting recall |
When you move from Classic to new Outlook, the biggest change is that you lose the 30-second delay and the manual Outbox control. The new Outlook feature is faster to configure but less flexible. If you frequently need more than 10 seconds to cancel a send, consider keeping Classic Outlook for accounts that support it. Microsoft plans to add more features to new Outlook over time, but the 10-second limit is by design for the current version.
Conclusion
You can now enable Undo Send in new Outlook by going to Settings > Mail > Compose and Reply and selecting a 5-second or 10-second delay. The feature works only with Exchange, Microsoft 365, and Outlook.com accounts. Unlike Classic Outlook, the message is sent immediately and you must click the Undo banner to recall it.
Test the feature with a message to yourself to confirm the banner appears and the recall works. If you need longer cancellation times, switch back to Classic Outlook or use the Rules > Delay Delivery option in Classic Outlook for individual messages. The new Outlook Undo Send is a quick safety net, not a full replacement for the Classic Outbox delay.