You Cannot Delete or Change E-Mail Messages That You Sent to a Mail-enabled Public Folder in Exchange 2007
Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.
This topic provides information about how to troubleshoot an issue in which you cannot delete or change e-mail messages that you have sent to a mail-enabled public folder in a Microsoft Exchange Server 2007 environment.
When you try to delete or change an e-mail message that you have sent to a mail-enabled public folder, you receive the following error message:
Microsoft Office Outlook - The item could not be deleted. It was either moved or already deleted, or access was denied.
However, you can delete or change items that you have posted to the public folder. This issue occurs if you are granted Author permission to the public folder. In this scenario, your permission settings are not preserved when you send the e-mail message to the public folder. Therefore, the store cannot match the initial author attribute of the e-mail message to the creator attribute of the e-mail message. Any modification of that item is denied. This issue does not occur if you are granted Owner permission to the public folder.
To work around this issue, use one of the following methods:
Obtain Owner permission to the public folder.
Use the post method instead of sending an e-mail message to the public folder.