When you try to log on to an Exchange 2000 or an Exchange 2003 mailbox by using a WebDAV program, you receive a 401 status code in Internet Explorer

When you try to access a Microsoft Exchange 2000 Server mailbox or a Microsoft Exchange Server 2003 mailbox by using a program that uses Web Distributed Authoring and Versioning (WebDAV), Microsoft Internet Explorer may return a 401 status code. Additionally, you may not be able to access the mailbox, and the following event may be logged in the application log:

Event Type: Error
Event Source: MSExchangeIS Mailbox Store
Event Category: Logons
Event ID: 1022
Description:
Logon Failure on database "Storage Group Name\Mailbox Store (Server Name)" - Windows 2000 account Domain Name\User Name; Mailbox /o=Organization/ou=Organizational Unit/cn=Recipients/cn=User Name.

This behavior may occur when either of the following conditions is true:

• The mailbox has never received an e-mail message, and a user has never logged on to the mailbox.
• The mailbox has received an e-mail message, but a user has never logged on to the mailbox.

To work around this behavior, log on to the mailbox by using one of the following clients before you run the WebDAV program:

• Log on to the mailbox by using a MAPI client such as Microsoft Outlook.
• Log on to the mailbox by using the Microsoft Outlook Web Access (OWA) client.
• Log on to the mailbox by using a custom application.

When a mailbox object is created in the Exchange information store, the mailbox object is not available by WebDAV until the mailbox is accessed through a client logon. If the mailbox receives an e-mail message, the mailbox object becomes available, but not in a way that permits the WebDAV program access. Therefore, the problem still occurs.