When running the new-mailboximportrequest I was getting the following error.
New-MailboxImportRequest is not recognized as the name of a cmdlet, function, script file
So to resolve this do the following.
1) Launch Exchange powershell
2) Run “Add-pssnapin microsoft*”
3) Run “install-CannedRbacRoles”
4) Run “Install-CannedRbacRoleAssignments”
5) Close powershell
6) Open up EMS and rerun command and it will work fine.