---
id: mac-storage-basics.what-is-filevault
url: https://storagestudio.us/faq/mac-storage-basics/what-is-filevault
category: "Mac storage basics"
subcategory: "Erasing, encryption and selling a Mac"
question: "What is FileVault, and does it slow down my Mac or use space?"
alt_questions:
  - "filevault mac explained"
  - "should I turn on filevault"
  - "filevault performance"
  - "filevault storage space"
  - "turn on disk encryption mac"
short_answer: "FileVault encrypts your startup disk, unlocked by your login password or recovery key. On modern Macs it has no noticeable speed or storage cost; keep the recovery key safe."
tags: ["filevault", "encryption", "security"]
related: ["https://storagestudio.us/faq/mac-storage-basics/how-do-i-encrypt-an-external-drive-on-a-mac", "https://storagestudio.us/faq/mac-storage-basics/how-do-i-erase-my-mac-before-selling-it"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What is FileVault, and does it slow down my Mac or use space?

**FileVault** encrypts your startup disk so its contents can't be read without your login password or recovery key. Turn it on in **System Settings → Privacy & Security → FileVault**.

On modern Macs it has no noticeable speed cost and doesn't use extra storage. Keep the recovery key safe — if you forget your password and lose the key, your data can't be recovered.