Can't use EAC to export to a PST file when the target user belongs to a child domain in Exchange Server 2013
Original KB number: 3173182
When you use the Exchange Admin Center (EAC) to export to a .pst file, and the target user account is in a separate child domain, you may receive the following error message:
The Operation couldn't be performed because object 'username' couldn't be found on domain.corp
This issue also occurs in the command shell when you run the
New-MailboxExportRequest cmdlet unless the
-DomainController switch is used and explicitly provides the name of a domain controller in the child domain in which the user exists.
This issue occurs if the Active Directory session that's responsible for searching the directory is scoped to the local domain. Because the user doesn't belong to the local domain, the user object isn't found.
To work around this issue, use the Exchange Management Shell with the
-DomainController switch, as in the following example:
New-MailboxExportRequest -Mailbox "User One" -FilePath \\server\share\export.pst -DomainController DC1.child.domain.corp