Event ID 1009 is logged when you use an application to access a shared mailbox by using the POP3 protocol in Microsoft Exchange 2007 Service Pack 1

Consider the following scenario in a Microsoft Exchange 2007 Service Pack 1 (SP1) environment:

• You use an application to access a shared mailbox by using the POP3 protocol.
• The account that you use to access the shared mailbox is not an associate account of the shared mailbox. However, the account has the full access permission on the shared mailbox.
• The application repeatedly connects to the mailbox.

In this scenario, you find that the application does not work as expected and the connections to the server are lost. When this occurs, the following event is logged in the Application log:

The POP3 protocol in Exchange Server 2007 SP1 defines a restriction of the max connection number for each user. When a connection is set, the corresponding counter increases by 1. When a connection is disconnected, the corresponding counter decreases by 1. When this problem occurs, this counter does not decrease when the connection is disconnected.

To resolve this problem, install Update Rollup 9 for Exchange 2007 Service Pack 1. For more information about Update Rollup 9 for Exchange Server 2007 Service Pack 1, 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.