I'm trying to setup a cross forest administration of exchange 2007, following this article http://technet.microsoft.com/en-us/library/bb232078.aspx . However, at step 9, I run the following command: Setup /prepareAD /ForeignForestFQDN:ForestA.contoso.com I get "Welcome to Microsoft Exchange Server 2007 Unattended Setup Preparing Exchange Setup Exchange Server setup encountered an error." It does not return any more of an error message. Their are no logs of this either. My issue appears to be exactly the same as the one detailed in this technet post http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/886672a4-567b-4df2-b430-156503085d19 . Thanks Brett

Figured it out..... I was running Setup.com from Exchange Management Shell... but needed to run it from the command prompt.