Troubleshooting the Mailbox Migration Tool

Following are troubleshooting tips to use when working with the Mailbox Migration tool.

Using the .csv file format. Some organizations have commas in their display names. If you use Microsoft Excel to create the .csv file, Excel automatically places quotation marks around any values that have commas in them. The tool treats a value surrounded by quotes as a single value.
Using the Tools.Clean Mailbox utility in the Microsoft Exchange Administrator. This removes only messages; it does not remove folders. Therefore, if a mailbox fails to migrate, the temporary folder will still exist. Trying to migrate after a cleanup causes a failure again, because the utility recognizes that the special temporary folder is present in the mailbox.
Deleting folders with the client application. If a mailbox has special folders that cannot be deleted by the client application (this may happen for Outlook users, because Outlook creates special folders for Calendar, tasks, and so forth, and will not let you delete them) and a migration fails, deleting the mailbox and recreating it is the best option.