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Delayed Sending in Outlook has problems and bugs

You can delay sending an email in Outlook. It’s a handy trick that can help make sure your message is read. Here’s how to schedule send an email plus the many traps, complications and a long-standing Outlook bug.

A Washington Post article headed The one simple trick to make sure your email gets noticed caught our eye because while delayed sending is a useful feature, it’s hardly ‘simple’.

Scheduling the timing of an email means it’s more likely to be noticed, instead of being caught up in the pile of emails that are usually waiting at the start of a day. It’s also a courtesy to the receiver who doesn’t have their personal time interrupted.

Outlook has an option to delay sending an email until future date or time – it looks simple but we found important details and bugs as we dug deep.

Delay Send on Outlook desktop (Windows/Mac)

For the Outlook desktop software (Windows or Mac) go to Options | Delay Delivery | Do not deliver before

Delay Delivery is a long-standing Outlook feature. Here it is in Outlook 2010 or Outlook 2007, looking a little different but the same feature.

Outlook 2010 - Delayed Sending image from Delayed Sending in Outlook and the bug at

Just set the date and time for sending then click ‘Close’. Finish writing the email as usual and click ‘Send’.

Simple – yes? Not so fast … like many things with Outlook (and Office) a simple thing is more complicated when we delved into it.

Delayed “Delivery”?

It might be thought a trivial point … Microsoft’s name for the feature is Delayed Delivery which isn’t right. All Microsoft and Outlook can do is send the email on or after the chosen time – not deliver at any particular time (or at all).

Google calls its similar feature ‘Scheduled Send’ and Apple says ‘Send Later’, both are more accurate labels.

Delayed message sits in Outbox

The schedule sent message will sit in the Outbox folder on your computer. That’s important and means there’s no guarantee that the email will be sent at the time you chose.

A Delayed Send email sitting in the Outlook desktop Outbox.

Why won’t the email go at the chosen time? There are two possibilities …

Outlook has to be running

Outlook software has to be running and connected at the send time. Obviously if Outlook isn’t operating and online, it can’t do anything. The delayed send message will go out when Outlook is next started. There’s a warning about this when you close Outlook with anything in the Outbox.

You might expect scheduled messages to be synced to the mail server (like Exchange Server or and sent from there at the right time … but that does NOT happen.

Send/Receive schedule

Strictly speaking, the scheduled email goes out at the next mailbox connection after the chosen time. That’s usually a few minutes after the send time and doesn’t matter a lot. However, the delay could be 30 minutes or more.

DON’T use Delayed Send for any kind of timely reminder or alarm. The scheduled sent isn’t that accurate.

The send time depends on the Send/Receive settings at Send/Receive | Send/Receive Groups | Define Send/Receive groups | Schedule an automatic send/receive every … minutes. The default is 30 minutes.

Even if Outlook is running, the message won’t go out at exactly the time you nominate – it will go at the next scheduled ‘Sent Items’ event after the delayed send time.

For example, you have Outlook scheduled to send messages every 15 minutes: 00, 15, 30 and 45 past the hour. A delayed message set for sending at 9:05am will sit in the Outbox for another 10 minutes until 9:15am when the next scheduled send event occurs.

This isn’t a problem for modern ActiveSync mailbox connections (mostly Microsoft 365 hosting, Exchange Server or because Outlook desktop maintains a constant connection. In our tests, scheduled messages went out within a few minutes after the desired time.

Time Zones

The Delayed Send time is according to the local computers time. Keep that in mind if you’re sending message to people in other time zones or are travelling but your laptop still uses your ‘home’ time setting.

When was the message sent?

A old ‘Delayed Send’ Outlook bug still hasn’t been fixed.

In the Sent Items folder, a delayed send message does NOT show the actual time of dispatch or even the scheduled time. The time shown is when the sender clicked the ‘Send’ button.

Delayed Send message as it appears in the Sent Items folder with incorrect send time.

In the above example, the message was delayed until 6:45am (see the subject line).

In fact, the message wasn’t sent until 11 minutes later and we only know that by checking the message header on the receiving machine. There’s no record in the users Outlook of when the message was really sent.

But that’s not the end of the confusion. We looked at the browser version of the same mailbox, hoping it might show more accurate information. Alas, it shows conflicting send times in the folder list (left) and the reading/preview pane (right).

Same delayed send email as above, but shown in the browser version of the mailbox.

When looked this feature in 2012 with Outlook 2010 it was the same misleading bug, the only difference was that browser-based mail wasn’t as common.

That detail is important when there’s a dispute about when a message was sent. The sender could allege a sending time well before when it was actually dispatched.

Back in 2012 Microsoft fell back on a standard excuse. They said Outlook was acting ‘as designed’.  We thought that Outlook not showing the actual time a message is sent was a classic bug that needed fixing. It seems nothing has been done in the last decade.

The only accurate record of when a message was really sent is held by the email receiver. They have the entire message header that should show full details of an emails path from one machine to another.

See Viewing an email message header in Outlook

Sending early a delayed delivery email

A delayed send email just sits in the Outbox until it’s time to go. If you change your mind, just double-click on the message, edit the contents (including removing or changing the delayed send time) then choose Send again.

Or select the Outbox message and delete it.

Message Header – Deferred-Delivery

The receivers copy of a delayed send message has all the details of an emails transmission.

From Exchange Server/ senders, there’s a “Deferred-Delivery:” line in the message with the time the email was set to go (not the actual send time).

Deferred-Delivery: Sat, 21 Jan 2023 14:45:00 +0000  

This message has a Delayed Delivery time of 2:45pm shown as UTC/GMT time (“+0000″_, not the time zone on the sending machine.

Why use delayed email?

So why would you use delayed email at all? I’m sure there are many situations, here are some:

  • Sending a press release or other document that is embargoed until a particular time.
  • Sending a message to someone in another time zone when you’ll be away from your computer but you want the message to appear during the receiver’s working day.
  • As a reminder or follow up for a task. If the person completes the task earlier than expected, remember to delete the delayed email from the Outbox.
  • Sending large emails at off-peak times to reduce the bandwidth usage. This applies when the Internet access is slow and large emails can ‘hog’ the limited bandwidth. We’ve had this problem when travelling and trying to share pictures – we use delayed sending to dispatch the images once we get back to somewhere with faster internet.

Viewing an email message header in Outlook

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