Question : This mailbox cannot be opened. The mailbox may be located in a different forest from the Microsoft Exchange Client Access server. For access to the mailbox or for more information, contact technical s

Hello there,
I am the Admin for exchange server 2007, My manager informed me that they might be letting someone in the company go. So i wanted to backup their PST file just in case. ( I perform daily backup on that server anyway). so i gave my self access to thire Box and i tried to access it first from OWA. to my surprise i am getting this error massage "This mailbox cannot be opened. The mailbox may be located in a different forest from the Microsoft Exchange Client Access server. For access to the mailbox or for more information, contact technical support for your organization"
what could the user have done to cause this error to happen???

Answer : This mailbox cannot be opened. The mailbox may be located in a different forest from the Microsoft Exchange Client Access server. For access to the mailbox or for more information, contact technical s

Has this mailbox been disconnected / disabled / deleted ?

Check disconnected mailbox here (Screenshots) and how to access that.

http://exchangeshare.wordpress.com/2008/04/27/cant-see-deleted-mailbox-in-disconnected-mailbox-under-recipient-configuration/