Hi all, I am using exchange 2010 sp1with windows server 2008 r2 sp1 if i am logged in to the domain ,i can download the OAB without any errors. but if i access the exchange from a computer not join to the domain even if this computer is joined to the domain but i am not logged in to this domain ,i cannot download OAB Any ideas?MCITP Enterprise Messaging Administrator, MCITP Enterprise Administrator, MCSE, MCDBA