Q&A: Locking Up the Mac I'm new to Macs. What is FileVault and do I need to use it? FileVault is a data-security feature built into the Mac's OS X operating system. With FileVault, you can encrypt the Mac's hard drive to keep its contents locked up with a password, even if someone gets access to your computer. FileVault can also encrypt the data on external drives and can be used to completely erase the Mac's hard drive when it comes time to recycle the computer. As to whether you need to use FileVault, it depends on your personal need for file security and keeping your data confidential. You can get a better idea of how it might fit into your computing life from Apple's current guide to the software on its site. Some versions of Windows include a similar feature, BitLocker.