We have an Exchange 2007 environment that has functioned in a Windows 2008r2 environment for years. The other night our Cisco Unity voice mail would no longer allow callers to leave our users voice mails. After spending hours with Cisco, we found a work around by manually adding each individual users email address to the email field on their active directory accounts. I did this using ADUC and made the entry on the general tab of each users account. This corrected our voice mail problem, but I am still not sure of the root issue. Today I tried to configure a new user on a workstation and opened OUTLOOK 2007, expecting it to find the users Exchange account and configure itself as I clicked NEXT. It did not find anything, but I was able to manually add the user to the local outlook the old fashioned way, after entering the server. This account did not have an email address added to it in Active Dirctory either. Today, I have had several people come to me and tell me their colleagues no longer show up in outlook when they go to send a new email and select TO: In other words some users were no longer appearing in the Global Address List. Each account missing, still did not have a manual entry of their email address in active directory. I am thinking there is something on longer working with our Exchange Auto Discover. I have never had to manually enter email addresses in active directory accounts before. All suggestions are welcome.