How to Export mailbox to .PST via Power Shell in Exchange 2010

Run powershell with Admin credentials and execute this command :  New-MailboxExportRequest –Mailbox “alias” –Filepath “\servernamesharefile.pst”

You might have to do all the following Steps before you run the above mentioned command:

Add a role in to your Exchange 2010:

New-ManagementRoleAssignment –Role “Mailbox Import Export” –User “Amdin-UserID”

Created a share with r/w permissions :

New-RoleGroup “Mailbox Import-Export Management” -Roles “Mailbox Import Export”

Add-RoleGroupMember “Mailbox Import-Export Management” -Member administrator
before the following would work : New-MailboxExportRequest –Mailbox “alias” –Filepath “\servernamesharefile.pst”