Just had to convert a load of Legacy Mailboxes created accidentally by a colleague who forgot to use the new Exchange 2007 console to create their mailboxes. Had about 350 new users so dong it manually wasn’t really an option!
Using the power of pipes in Exchange 2007 Shell you can run the following command to upgrade all legacy mailboxes to user mailboxes. Do make sure that you want to do this before hitting enter. You can filter the affected users even more if you wish.
Get-Mailbox -RecipientTypeDetails LegacyMailbox | Set-Mailbox -ApplyMandatoryProperties
