Deferred Delivery Behavior in Outlook and Exchange 2003

Friday, August 17, 2007
Over time I've fielded a lot of questions about deferred delivery behavior using Outlook and Exchange Server 2003. The purpose of this post is to try and clear up some of the confusion.

Users can defer delivery using Outlook 2003/2007 by selecting the "Do not deliver before" date and time in Delivery Options of a message. This is done from the View Options menu of the new message:


My example message was sent at 12:04pm and schedule to be delivered at 12:10pm. Once sent, the email will stay in the Outbox until 12:10pm. If the sender isn't using Cached Exchange Mode, the email actually resides on the Exchange server. This means you can close Outlook and the email will still be delivered at the scheduled time. If the sender is using Cached Exchange Mode, Outlook needs to be running for the email to be delivered at the scheduled time.

Once the email is sent, it shows in the sender's Sent Items folder as being sent when the user clicked the Send button (12:05pm instead of 12:10pm). Outlook rounds the seconds up or down, which accounts for the lost minute.


When the recipient receives the email at the scheduled time, it shows in the recipient's Inbox as received at 12:11pm. This is the time the Exchange server delivered the message to the recipient's Inbox. Again, the time is rounded up by Outlook to show that it was received at 12:11pm:


When the recipient opens the email, he will see the email was sent at 12:05pm. This is the time the user clicked the Send button.



If we track the message through the Exchange Message Tracking Center, we will only see when the message was actually in transport through the Information Store. Note that there is no indication in message tracking that this message was sent with deferred delivery:


Taking a look at the SMTP headers, we see that the email was sent at 12:04:52.



Microsoft Mail Internet Headers Version 2.0
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: application/ms-tnef;
name="winmail.dat"
Content-Transfer-Encoding: binary
Subject: Email written at 12:04pm
Date: Thu, 16 Aug 2007 12:04:52 -0700
Message-ID: <7B569F3F3E4DF34A86878A85F5CB7B8F0124020E@hoem01.scif.com>
X-MS-Has-Attach:
X-MS-TNEF-Correlator: <7B569F3F3E4DF34A86878A85F5CB7B8F0124020E@hoem01.scif.com>
Thread-Topic: Email written at 12:04pm
Thread-Index: AcfgOE14IdGWt/ZvRTS3VBrfx1yACQ==
From: "Jeff Guillet" <jsguillet@sscif.com>
To: "Brian Peladeau" <BPeladeau@sscif.com>

Hopefully, this helps clear up some of the confusion about deferred delivery.