Running Exchange 2003, the IS department has several OU admins throughout the organization that maintain their OU. In the process of creating a user, the Exchange mailbox option to select the mailstore dropdown is blank. I have given the OU admins group Exchange Admin View only rights to that organization and to the administrative group and the dropdown box is still blank. Do I need to give them specific rights on each of the information stores? I have tested this out in a lab enviroment and it works with just being an Exchange Admin View only. It is 4 node active/passive cluster with two active nodes.

If you've got a lab mirrored, use ADSIEDIT to look at the configuration container permissions throughout the exchange org to find the difference.