Exchange 2000's security is improved over previous versions in several areas. One important change is that no account has access to the organization's mailboxes by default. Access must be specifically assigned if someone needs to open a mailbox with something other than the mailbox's primary account.
Unfortunately, this security improvement makes some tasks more difficult. For example, backup software that copies individual mailboxes usually requires permission to open the mailbox. With older versions of Exchange, you could simply create an account, grant Service Account permissions at the site or organization level, and associate that account with the backup program. Exchange 2000 forces you to assign the account associated with the backup program to each mailbox you wish to open.
Follow these steps to grant permission to open a mailbox in Exchange 2000:
The user or group selected in Step 5 now has full access to the mailbox.