A common problem with mailbox migrations to Exchange 2007 is Legacy Mailboxes getting placed on an Exchange 2007 server.
What are the symptoms the user will experience? The user will still be able to access their e-mail via Outlook; however, they will receive an interesting error when they try to connect via OWA. The following is the error that will be displayed:
Exception type: Microsoft.Exchange.Data.Directory.InvalidADObjectOperationException
Exception message: Property Languages cannot be set on this object because it requires the object to have version 0.1 (8.0.535.0) or later. Current version of the object is 0.0 (6.5.6500.0).
How does a Legacy Mailbox find its way to an Exchange 2007 server? Excellent question! If you use Active Directory Users & Computers to Mail-enable a user for Exchange 2007, it will happen every time. I would highly recommend that you completely uninstall the Exchange 2003 Management tools off of all of your computers to prevent these legacy mailboxes from being created.
How do I convert the Legacy Mailbox to an Exchange 2007 mailbox? Not to difficult at all....open up Exchange Shell and enter the following: