Hi, What is association external account permission? For what features it used for? As per my knowledge it is used for to delegate the OWA External forest users to open the mailbox. But I have two windows 2003 forest, I am successfully able access the mailbox which's on other forest using Owa without giving external associated permission. I have given only full rights. Is associated External Account is only applicable when we have want to associate the mailbox to the NT users? Thanks, Manjeet