Mailbox Move Error

SYMPTOMS
When you use the Active Directory Users and Computers snap-in to move an Exchange 2000 user or an Exchange 2003 user from one server to another, the Exchange Task Wizard may report the following error message:
Error: Connecting to destination server. cn=newuser,,CN=Users,DC=regency,DC=com The attempt to log on to the Microsoft Exchange Server computer has failed. The MAPI provider failed. Microsoft Exchange Server Information Store ID no: 8004011d-0512-00000000

CAUSE
These errors are reported because Move Mailbox cannot log on to the system attendant mailbox. The system attendant has a mailbox on each server, usually on the default mailbox store.

RESOLUTION
Make sure that the default mailbox store is mounted.

MORE INFORMATION
The following error messages may be reported in the event log:

Event Type: Error
Event Source: MSExchangeAdmin
Event Category: MAPI Session
Event ID: 9175
Date: 5/31/2000
Time: 4:53:05 PM
User: N/A
Computer: ServerA
Description: The MAPI call 'OpenMsgStore' failed with the following error:
The attempt to log on to the Microsoft Exchange Server computer has failed. The MAPI provider failed.
Microsoft Exchange Server Information Store
ID no: 8004011d-0512-00000000

Event Type: Error
Event Source: MSExchangeAdmin
Event Category: Move Mailbox
Event ID: 9167
Date: 5/31/2000
Time: 4:53:05 PM
User: N/A
Computer: ServerA
Description: Unable to get an administrative interface to the mailbox store on server 'ServerA'.
Error: The attempt to log on to the Microsoft Exchange Server computer has failed. The MAPI provider failed.
Microsoft Exchange Server Information Store
ID no: 8004011d-0512-00000000

Event Type: Error
Event Source: MSExchangeAdmin
Event Category: Move Mailbox
Event ID: 1008
Date: 5/31/2000
Time: 4:53:05 PM
User: N/A
Computer: ServerA
Description: Unable to move mailbox 'newuser'.
Error: The attempt to log on to the Microsoft Exchange Server computer has failed. The MAPI provider failed.
Microsoft Exchange Server Information Store
ID no: 8004011d-0512-00000000

This exert is taken from Microsoft's Technet Page. Microsoft Name belongs to Microsoft Corp.