Hi,
we have migrated from Exchange 2007 to Exchange 2013. We built a new Exchange 2013 organization with new Active Directory... All new :)
After exporting all mailboxes to PST's, we imported them using new-mailboximportrequest...
Everything works fine except answering older mails.
When the recipient was inside the old Exchange Organization, Outlook sends back an NDR, that the recipient could not be found.
When we choose the recipient again from Outlook Addressbook, then it works.
How can i now update all old mails with the right recipient information ?