Metadata refers to hidden data within electronically stored information that can include details like author name, edit history and more. While metadata can be beneficial for authentication and collaboration, it also poses risks if it reveals weaknesses in a legal case or was inappropriately modified. Though metadata cannot be fully avoided, its creation can be minimized and removal methods exist, but are not always fully reliable. Lawyers should be aware of metadata issues and implement policies and training to safely manage electronically stored information.