Review generated emails with a timed draft delay

This starts a real campaign with a countdown, not an approval step. Microsoft 365 sends the generated messages automatically when the delay ends, even if Outlook is closed. Use a test email and recipient review first.

Updated October 2026

Choose the right kind of review

• Check your recipient data and exclusions: Review and unselect recipients before starting the campaign. This does not send anything.
• Check formatting and merged values for the first recipient: Send a test email to yourself. It goes to you instead of your recipients.
• Inspect generated emails in Drafts: Follow this guide to start a campaign with “Delay before the first message”. It sends automatically when the delay ends; it does not wait for you to approve the drafts.

The maximum delay is ten minutes. For a large campaign or large attachments, this may not leave enough time to generate and inspect every message. Start with a small list of addresses you control if you need to try this workflow.

Step 1. Open advanced options

In the campaign manager select the link that shows or changes advanced options. The advanced options reference describes the whole screen, including what carries over to your next campaign.

The preview delay lives in the “Schedule” group, in the “How fast” subgroup, alongside “Delay between messages”. Its label in the add-in is “Delay before the first message”.

Step 2. Set “Delay before the first message”

This setting was previously labelled “seconds preview delay”. All messages will be generated but set to delay their sending by the specified amount. This also works in conjunction with delay between messages. In that case the first message is delayed by the delay before the first message, the second by that delay + number of seconds between messages and so on.

SecureMailMerge generates the messages in your Drafts folder while Outlook is open, then hands them to Microsoft 365 with a send time using Outlook’s own scheduled send. Once the preview delay has passed, Microsoft 365 sends them whether or not Outlook or your computer is on.

Maximum value

The maximum delay before the first message is 10 minutes (600 seconds).

Step 3. Generate and inspect the drafts

Once the delay is set, first send a test message if you haven’t already, and then send the campaign. The messages will be generated but will not be sent until the delay has passed.

Open your mailbox in new Outlook or Outlook on the web and inspect the generated recipient messages in Drafts, including their scheduled times. They are separate from your template draft, the email you composed the campaign in. Classic Outlook may not show their scheduled time. Check recipient-specific values and attachments before each message’s send time.

Note: This feature will NOT apply to test emails. Test emails will be sent immediately.

Tip: If you only want to skip some recipients rather than review every generated email, you can unselect them in the recipient preview before sending.

If you find an error

1. If the add-in is still generating messages, cancel the campaign (or pause it) to stop generating more. This does not cancel the recipient messages already scheduled with Microsoft 365.
2. Open the same sending mailbox in Outlook on the web and delete the campaign’s generated recipient messages from Drafts before their send times. Check the subject and recipients so you do not delete your template draft or unrelated drafts. Deleting your template draft does not stop any message.
3. Refresh Drafts and confirm the deleted messages no longer appear there in Outlook on the web.

The full steps, including which mailbox to open when you send from an alias or shared mailbox, are in Stop messages that are already scheduled. To start a campaign on a later day instead, see How do I schedule my mail merge for a specific day?.