1. Firstly log onto a Exchange 2010 server.
2. Then Open “Exchange Management Shell”
3. If this is the first time you are exporting a mailbox in Exchange 2010 then you will need to run the following command in the shell to grant yourself the relevant permissions to export a mailbox (change the red to suit your needs):
New-ManagementRoleAssignment –Role “Mailbox Import Export” –User DOMAIN\YOUR_ADMIN_ACCOUNT
4. Now log out and back in.
5. The following will export command will export a mailbox to a server share:
New-MailboxExportRequest -Mailbox A.Example@EmailAddress.com -FilePath "\\SERVER\SHARE\Administrator.pst"
6. The request will enter into a Queue and run when resources permit, to check on the progress you can use the following command:
Get-MailboxImportRequest | Get-MailboxImportRequestStatistics