The Undo Send feature in Gmail allows users to retract a message right after it is sent. Undo Send operates by creating a brief delay in the sending process.  You can select one of four delay timeframes in which a message can be "unsent", allowing you to recompose the message or make corrections before resending to recipients...or deleting entirely. The sections below detail activating and implementing the feature.

Contents:

Follow the steps given below to activate Undo Send in your Gmail account.

1. Open Gmail and click on the Settings (Gear) icon located on the top right of the screen. 
2. In the pop-up menu, click on Settings.
3. On the General Settings tab, scroll down to the section titled Undo Send.
4. Check the box next to Enable Undo Send.
5. In the Send cancellation period section, select the amount of time delay you desire for Undo Send.
   • 5, 10, 20, and 30 second delay times are currently supported.
6. Scroll to the bottom of the page and click Save Changes.
7. Undo Send will now appear in a yellow banner at the top of the Gmail window whenever you send a message.

After activating Undo Send, an Undo button will now appear in a yellow banner at the top of the Gmail window whenever you send a message.  To cancel the sending/delivery of a message:

1. Click the Undo button in the yellow banner.
2. Your message will re-open in the Compose window, allowing you to make corrections or changes to the message, recipients, subject or attachments.
3. Once you have finished revisions, click Send.
   • You can also Delete the message or save it in Drafts at this stage, if desired.
4. Repeat as necessary.

Note: If you miss the chance to Undo Send a message, you may want to consider extending the time delay on the Undo Send feature in Settings.