You set the system locale of a Microsoft Exchange Server 2003 server to a non-English language in a mixed Microsoft Exchange Server 2010 and Exchange Server 2003 environment. For example, you set the system locale of an Exchange Server 2003 server to Japanese.
You select an external recipient as the forwarding address for an Exchange Server 2010 user mailbox.
The Exchange Server 2010 user’s display name contains double-byte character set (DBCS) characters.
An Exchange Server 2003 user sends an email message to the Exchange Server 2010 user.
In this scenario, the email message is forwarded incorrectly to the external recipient. For example, the external recipient may receive a duplicated email message. Additionally, the following error message is logged in SMTP log on the Exchange Server 2010 server:
500 5.5.2 Error processing XEXCH50 command
This issue occurs because the Exchange server 2010 server incorrectly treats the ANSI string as an ASCII string during the decoding process. This causes the XEXCH50 command failure.
To resolve this issue, install the following update rollup:
2661854 Description of Update Rollup 2 for Exchange Server 2010 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the upgrade from Exchange Server 2003 to Exchange Server 2010, visit the following Microsoft website: