The nickname of a mail user must be unique in a forest if you use the original release version of Exchange 2007

In a Microsoft Exchange Server 2007 environment, the nickname of a mail user must be unique in a forest. This may cause some inconveniences in a hosting environment.

This problem occurs if you use the original release version of Exchange 2007.

To resolve this problem, install Update Rollup 3 for Exchange Server 2007. For more information about Update Rollup 3 for Exchange Server 2007, see the following Exchange Help topic: For more information about how to install the latest Exchange service pack or update rollup, see the following Exchange Help topic:

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: For more information about Exchange Server software updates, click the following article number to view the article in the Microsoft Knowledge Base: