Email remains in the Outbox when you use the DelegateSentItemsStyle registry value

Original KB number:   2703723

When you send an email message from a shared mailbox, the sent email message remains in your Outbox until you manually perform a Send/Receive operation.

This problem occurs when all the following conditions are true:

• Your Outlook profile is configured in online mode (not cached Exchange mode).
• You have the DelegateSentItemsStyle registry value set to 1.

You can resolve this issue by using one of the following methods. If these methods are not acceptable, see the Workaround section for additional options.

If you set DelegateSentItemsStyle=0 in the registry, email messages that you send from a shared mailbox will be copied to your Sent Items folder and not the Sent Items folder of the shared mailbox.

1. Exit Outlook.

2. Start Registry Editor. To do this, use one of the following procedures, as appropriate for your version of Windows.

   Windows 8 and Windows 10: Press Windows Key+R to open a Run dialog box. Type regedit.exe and then press OK.

   Windows 7 or Windows Vista: Select Start, type regedit in the Start Search box, and then press Enter. If you are prompted for an administrator password or for confirmation, type the password, or select Allow.

   Windows XP: Select Start, select Run, type regedit, and then select OK.

3. Locate and then select the following registry key:

   HKEY_CURRENT_USER\Software\Microsoft\Office\<x.0>\Outlook\Preferences

   Note

   In this key path, the placeholder <x.0> represents 16.0 for Outlook 2016, Outlook for Microsoft 365 and Outlook 2019, 15.0 for Outlook 2013, 14.0 for Outlook 2010, 12.0 for Outlook 2007, and 11.0 for Outlook 2003.

4. Select the DelegateSentItemsStyle value.

5. On the Edit menu, select Modify.

6. Type 0, and then select OK.

7. Exit Registry Editor.

8. Start Outlook.

If you must have the functionality that is offered by the DelegateSentItemsStyle registry value (=1), your other option is to change your profile from online mode to cached mode.

Outlook 2010 and later versions

1. On the File tab, select Account Settings, and then select Account Settings.
2. On the E-mail tab, select your Exchange Server account, select Change, and then enable the Use Cached Exchange Mode option.
3. Select Next, and then select Finish.
4. Exit and restart Outlook.

Outlook 2007

1. On the Tools menu, select Account Settings.
2. On the E-mail tab, select the Exchange Server account, and then select Change.
3. Under Microsoft Exchange server, select to select the Use Cached Exchange Mode check box.
4. Select OK.
5. Exit and restart Outlook.

Outlook 2003

1. On the Tools menu, select E-mail Accounts.
2. In the E-mail Accounts dialog box, select View or change existing e-mail accounts, and then select Next.
3. Select the Exchange Server account, and then select Change.
4. In the E-Mail Accounts dialog box, select the Use Cached Exchange Mode check box, and then select Next.
5. Select OK, and then restart Outlook.

If the methods provided in the Resolution section are not acceptable, and if your mailbox is located on Microsoft Exchange Server 2010 Service Pack 2 Update Rollup 4 or later version, or Exchange Server 2013 Cumulative Update 9 or later version or Microsoft 365 Exchange Online, the Exchange administrator can configure similar behavior on the server. These configurations do not require the DelegateSentItemsStyle registry key to be enabled, therefore the issue will not occur.

Update Rollup 4 for Exchange Server 2010 Service Pack 2 introduced a new Exchange PowerShell cmdlet to configure the Sent Items folder to which a message is copied. Because this new feature is handled by the Exchange server, Outlook can be configured for online or cached Exchange mode. However, the Exchange server feature works only if the Outlook DelegateSentItemsStyle registry value is disabled.

For more information about the Set-MailboxSentItemsConfiguration cmdlet, see Messages sent by using the "Send As" and "Send on behalf" permissions are only copied to the Sent Items folder of the sender in an Exchange Server 2010 environment.

Cumulative Update 9 for Exchange Server 2013 introduced a new feature that allows administrators to configure the Sent Item folder to which a message is copied. Because this new feature is handled by the Exchange server, Outlook can be configured for online or cached Exchange mode. Note that if you enable this feature and enable the DelegateSentItemsStyle registry value with a cached Outlook profile at the same time, two copies of the sent item will be saved in the shared mailboxes Sent Items folder.

For more information about this feature, see Want more control over Sent Items when using shared mailboxes?.

The DelegateSentItemsStyle registry value is stored in the following location in the Windows registry:

HKEY_CURRENT_USER\Software\Microsoft\Office\<x.0>\Outlook\Preferences

The functionality that is provided by the DelegateSentItemsStyle registry value is described in When you send an e-mail message from a shared mailbox in Outlook 2007, the sent message is not saved in the Sent Items folder of the shared mailbox.