A content management system enriches contact records obtained from a client device using user records stored on the content management system. The content management system receives contact records from a client device authorized on a user account of the content management system. The content management system compares contact records with user profiles stored on the content management system. The content management system matches contact records with user profiles of user accounts with which at least one sharing event occurred between the user account and the user account on which the client device is authorized. The content management system identifies a matching user profile corresponding to the contact record. The content management system determines modification information for modifying the contact record based upon the matching user profile.