Today, at a customer site, I addressed a problem that annoyed users more than usual. It seems that they can't sign up for alerts or assign each other tasks, and they get an error screen that offers to fix the problem, but leads to a dead end. I evaluated it, and created this write-up: Among the many pieces of information collected and presented by SharePoint, some of this information comes directly out of Active Directory. AD was always intended to be a directory first, a central repository for information about users, phone numbers, email, etc. I’ve seen phone systems that tap directly into AD, for example. But most places I’ve been, AD is simply treated as a place to store user accounts, and much of the information on each account is left blank. SharePoint’s strength (or weakness, if you’re a cynic) is that is depends on AD for certain pieces of information. MOSS periodically queries AD and updates all user profiles with this information, such as who works for whom, phone numbers, department information, and email addresses. Problem: It’s this last piece of information that, when missing, breaks some functionality in SharePoint. In order for people to be able to sign up for alerts (e.g. to be notified when a document is changed, an item is added to a list, or status changes on a task), or be assigned tasks, or a multitude of other collaborative processes, the email address field must be populated in AD. Otherwise, they get an error like this: And if they click the friendly...