I came across an interesting question from a client a few months ago. The client was a small 100 user law firm that needed to mimic what their Nortel BCM 400 was able to do and that was to create a general voice mailbox. His question was whether he can just enable a user account named “General Voice Mailbox” for Exchange 2007 UM but not email.
The GUI obviously doesn’t allow you to do that since it only displays users with mailboxes so I went ahead and asked a Microsoft engineer in the Partner Forums and was told that this wasn’t possible. Here’s the answer I got:
Based on my research, we are not able to enable UM for a user object without enabling mail. The UM features are based on the basic mail features provided by the Exchange servers. For example, the Missed Called Notification is sent via e-mail. If a user object is not mailbox-enabled, this user is not able to receive the notification.
What I ended up doing was enabling the user for messaging then hiding the user from the GAL and set the account to not accept messages from anyone.
I did some searches over the internet when I was trying to figure this out and wasn’t able to find any hits so I figure I post here in case someone does the same in the future.