We have a root domain\child domain setup.
The root domain contains exchange 2003, the child domain contains an exchange 2007. Exchange 2007 has successfully installed. We are in the process of migrating the mailboxes to to the child domain (exchange 2007) from the root domain. The user accounts for the time being are going to stay in the root domain. The mailboxes suceesfully migrate, however when the user tries to access the mailbox he/she is prompted for an username\password. If I add the user to the domain admin groupmof the parent domain the user can access the mailbox okay. I feel that the issue is AD rather than Exchange. Can anyone enlighten as to where and what permission i need to allow the user to access the mailbox on the child domain without granting them admin status.