Apple Certified Support Professional (ACSP) Practice Exam 2025 - Free ACSP Practice Questions and Study Guide

Enabling FileVault on a volume is a security feature that encrypts the data stored on that volume. This encryption process protects sensitive information by converting it into a format that can only be accessed with the proper decryption key, typically the user's password. By encrypting the entire volume, FileVault ensures that even if someone gains unauthorized access to the physical drive or the data is copied, they would not be able to read the contents without the decryption key.

The other options do not capture the primary function of FileVault. While backing up data is an important practice, FileVault itself does not perform backups. Increasing volume capacity is related to storage management but does not pertain to FileVault's purpose. Similarly, optimizing performance involves improving how quickly and efficiently data can be accessed or processed, which is not an objective of FileVault. Therefore, the correct choice highlights the essential role that FileVault plays in securing data through encryption.