- You have the Microsoft Exchange Server 2013 Client Access Server role installed in a Microsoft Exchange Server 2010 environment.
- The Exchange Server 2013 Client Access Server role is published through a firewall or a proxy server, such as Microsoft Forefront Threat Management Gateway (TMG).
- You have a mailbox that is located on an Exchange Server 2010 Mailbox server.
- You log on the mailbox in Outlook Web App by using Internet Explorer 8, Internet Explorer 9, Internet Explorer 10, or Internet Explorer 11.
- Internet Explorer uses Microsoft Silverlight.
When you perform a bulk deletion or a bulk move of email messages, the operation fails, and you receive the following error message: