Online backup was taken successfull and then 1 mailbox was moved to another mailbox store. Then due to some old email deletion, user reuested to retrive that email.
When we restore that backup in Recovery Storage Group/other production store, we will not be able to merge the data (E2K3 SP2 feature) or use exmerge since that AD account already have mailbox in another store (as we moved it after backup).
It fails with this error: The Operation cannot be performed because this mailbox was already reconnected to an existing user. ID no. c1034ad6. Exchange System Manager