Full Disk Access (FDA) is a macOS security feature that controls which applications can access all files on your system, including sensitive data such as emails, messages, and system files. By default, most apps are restricted from accessing certain protected locations. Granting FDA to an application allows it to bypass these restrictions, which is sometimes necessary for antivirus tools, backup software, or system utilities to function properly. However, enabling FDA for untrusted applications can pose significant security and privacy risks, as it gives them the ability to read, modify, or delete any file on the disk. Users should carefully manage which apps receive FDA permissions.