I was recently attempting to run a mailbox export request to a PST file in Exchange 2010 Service Pack 3, on running the New-MailboxExportRequest cmdlet, I was presented with the following error message:
The term "New-MailboxExportRequest" is not recognized.
In order to resolve this issue I had to grant the account performing the export request the ‘Import Export Mailbox’ role assignment as below.
New-ManagementRoleAssignment –Role “Mailbox Import Export” –User "DOMAIN\USER"
Once I restarted my powershell session, I was able to succesfully run the New-MailboxExportRequest cmdlet.