When you attempt to migrate a mailbox stored on Exchange 2007 to Exchange 2010, you receive the below errors:

Error occurred in the step: Preparing mailbox to be moved. Failed to copy basic mailbox information with error:  A duplicate mailbox was found due to problems during a Move Mailbox procedure. The duplicate mailbox has been deleted.
Try again later., error code: -1056749241

and

Error occurred in the step: Opening destination mailbox. An internal processing error due to a bad parameter has occurred.
Try restarting the Exchange System Manager or the Microsoft Exchange Information Store service, or both., error code: -1056696538

Resolution:
Logon to Exchange 2010 server and move the mailbox from there. Works without errors.