"Can’t open this item" error message when you use Outlook 2003 in online mode in an Exchange Server 2010 environment

Applies to: Exchange Server 2010 EnterpriseExchange Server 2010 Standard

Symptoms


When you use Microsoft Office Outlook 2003 in online mode to access your mailbox in a Microsoft Exchange Server 2010 environment, you may be unable to open the message item. Additionally, you receive the following error message:
Can't open this item.
Note This issue typically occurs when the message item contains many recipients and the message status is unread.

Cause


This issue occurs because the Exchange Server 2010 server adds the RopNotify remote operation (ROP) response after the RopBufferTooSmall response when it detects that the remote procedure call (RPC) buffer is insufficient. Then, Outlook 2003 resends the data that is followed by the RopNotify response. However, the Exchange Server 2010 server does not expect the RopNotify response and returns the ecRpcFormat error code.


Resolution


To resolve this issue, install the following update rollup:
2645995 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 2

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information


For more information about the RopBufferTooSmall response, visit the following Microsoft website:For more information about the RopNotify response, visit the following Microsoft website:For more information about the ecRpcFormat error code, visit the following Microsoft website: