You cannot move mailboxes to a Microsoft Exchange Server 2007 server. In this situation, the movement task is stuck in an infinite loop during the mailbox moving procedure. Additionally, the CPU usage is very high.
This issue occurs when some email messages in the mailboxes have an invalid PidTagChangeNumber property.
To resolve this issue, install the following update rollup:
2407025 Description of Update Rollup 2 for Exchange Server 2007 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the PidTagChangeNumber property, visit the following Microsoft website: