Moving More Mailboxes At The Same Time, Especially During Migration...

Moving mailboxes to an Exchange 2007 server is a time consuming task in an inter-forest migration and you can only use the move-mailbox cmdlet. By default, you can only move 4 mailboxes simultaneously. This makes things very difficult if you have thousands of mailboxes to be moved.

You can increase the number of mailbox move threads from 4 to a maximum of 30 by adding a switch to the move-mailbox cmdlet. Run the command

Get-Mailbox -Server CurrentServerName | Move-Mailbox -TargetDatabase "NewServer\SG1\DatabaseName" -MaxThreads 30

Though you can specify any value between zero and 30, make sure you give an appropriate value depending upon your network.