We are running Exchange 2007 SP1 (rollup 8) on a Windows 2008 server. I have two domains A and B that trust each other. Exchange is on Domain A. When I go to add "Full Access Permission" to a mailbox for a user from Domain B, I can't get the Domain B users so show up. I go to add/modify recipient picker scope/browse and only Domain A is there. No sign of Domain B This forces me to go to an Exchange 2003 server. Fire up ADUC and add the user from Domain B. When I go back to my Exchange 2007 box and click on the mailbox, there is my Domain B user happy as a clam, no crazy SID or something, just the friendly name. What gives? It is driving my Domain B admins nuts.

Is domain B available in same AD forest or different and which trust you have between Domain A and Domain B?Amit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com

thanks for your reply. no B is not in the same forest. two totally separate domains connected by a bi-directional trust. worked great in exchange 2003, seems to be having issues in 2007.

The wizard can only handle objects within the same forest, but if you use powershell and the Add-MailboxPermission. You should be able to grant users outside Exchange forest permission to Exchange objects.lasse at humandata dot se, http://anewmessagehasarrived.blogspot.com

Yes, as Lasse said, administration model has changed in Exchange 2007 management tools.. In Exchange 2003, it was attached with ADU&C (which is intended to do cross forest AD administration) and we used to handle administration of Exchange along with AD but in Exchange 2007, you need to follow below article to configure cross forest administration. How to Configure Cross-Forest Administration http://technet.microsoft.com/en-us/library/bb232078.aspxAmit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com