One of the most valuable security features in macOS is FileVault. FileVault encrypts the data on the startup disk and prevents unauthorized access by anyone who doesn’t have the decryption key or the correct account login credentials. FileVault is more than just a password protection security feature – while ordinary passwords prevent unauthorized access to a computer, they can be bypassed if a hacker removes the hard drive from a Mac and connects it to their computer as a secondary hard disk.