DirSync errors

The DirSync errors report shows all objects that are experiencing a conflict in DirSync. In our experience, many of these errors are false alarms, or at least not particularly serious. However, keep in mind that all high-level admins will get emails alerting them to their (continued) existence. These issues are caused when properties that are supposed to be unique—for example, the UserPrincipalName—are assigned to more than one record. A common cause of this would be the existence of a mail contact within a distribution group with the same email as a guest user. Clicking on the object in error will give you more details on how to resolve the error.