To work around this issue, use one of the following methods.
Method 1: Set the DelegateSentItemsStyle registry value on the Outlook clientNote Outlook must be configured to run in cached mode for this option to work correctly. For more information, see the following Microsoft Knowledge Base article:
If you're running Outlook 2010, install the Outlook 2010 hotfix package that's dated December 14, 2010. Then, follow these steps.
For more information about this hotfix package, see the following Microsoft Knowledge Base article:
Note If you're running Outlook 2013 or a later version, you don't have to install any hotfix.
- Click Start, click Run, type regedit, and then click OK.
- Locate and then click the following registry subkey:
HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\PreferencesNote The x.0 placeholder represents your version of Office (16.0 = Office 2016, 15.0 = Office 2013, 14.0 = Office 2010).
- On the Edit menu, point to New, and then click DWORD Value.
- Type DelegateSentItemsStyle, and then press Enter.
- Right-click DelegateSentItemsStyle, and then click Modify.
- In the Value data box, type 1, and then click OK.
- Exit Registry Editor.
Method 2: Configure the mailbox to save a copy of the message to the Sent Items folder of the shared mailbox in Exchange Online or in on-premises Exchange Server
Exchange Online in Office 365 or Exchange Server 2013 Cumulative Update 9 or later updateCumulative Update 9 for Exchange Server 2013 introduced a new feature that lets administrators configure the Sent Items folder to which a message is copied. For more information, see Exchange Blog - Want more control over Sent Items when using shared mailboxes?
Exchange Server 2010 Service Pack 2 Update Rollup 4 or later updateUpdate 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 server that's running Exchange Server, Outlook can be configured in online mode or cached Exchange mode. However, this feature works only if the Outlook DelegateSentItemsStyle registry value is disabled.
For more information about the Set-MailboxSentItemsConfiguration cmdlet, see the following Microsoft Knowledge Base article:
Note The MessageCopyForSentAsEnabled and MessageCopyForSendOnBehalfEnabled settings are not supported if the user mailbox and shared mailbox are located in different environments (cloud and on-premises). The settings are supported only if both mailboxes are in the same environment (cloud or on-premises).