How To Encrypt A Document On Mac | 4 Built-In Methods Compared

To encrypt a document on Mac, use Preview for PDFs, Microsoft Word for documents, Disk Utility for folders, or FileVault for the whole drive.

To learn how to encrypt a document on Mac, you don’t need extra software. Apple includes several built-in tools that handle different types of files, and picking the right one depends on what you’re protecting. A single PDF, a Word file, a folder of tax records, or your entire startup disk each calls for a different approach — and macOS has a native option for every one of them.

Encrypting A Document On Mac: Choosing The Right Method

The four main built-in options cover nearly every scenario. Preview handles PDFs, Microsoft Word secures its own documents, Disk Utility wraps files and folders in an encrypted disk image, and FileVault locks down the entire startup disk. The table below shows how each method compares, so you can pick the one that fits your situation.

Each method works on current versions of macOS and requires no subscription. The trade-off is always the same: without the password or recovery key, the data stays locked — permanently.

How Do You Password-Protect A PDF In Preview?

Preview lets you export a password-protected copy of any PDF without additional software. Open the PDF in Preview, choose File > Export, click the Permissions button, then select Require Password To Open Document. Enter and verify your password, optionally set an owner password to restrict printing or editing, click Apply, then Save. The exported copy will prompt for a password every time someone opens it. One thing to know: this creates a new encrypted copy — it leaves the original file untouched.

Encrypting A Word Document In Microsoft Word

Microsoft Word for Mac has built-in document encryption that works independently of macOS. Open the document, go to Review > Protect > Protect Document, enter a password in the Set a password to open this document field, click OK, re-enter the password, then save the file. Word passwords are case-sensitive and capped at 15 characters in this workflow. The document will show a lock icon and demand the password before displaying its contents. If you remove the password later and save again, the protection is gone, so keep a secure copy of any password you set.

Locking Files And Folders With Disk Utility

Disk Utility can bundle any group of files into an encrypted disk image — a single .dmg file that requires a password to mount. Open Disk Utility, choose File > New Image > Image from Folder, select the folder, then pick either 128-bit AES or 256-bit AES encryption. Enter and verify a password, choose Read/Write if you need to add or remove files later (or Read-Only for a fixed archive), and save the .dmg. On Macs running macOS 10.13 or later, selecting APFS or APFS (Case-sensitive) as the format gives the best compatibility. The .dmg file will mount and show its contents only after the correct password is entered. If that password is lost, the data inside is unrecoverable — Disk Utility offers no backdoor.

Turning On FileVault For Full-Disk Protection

FileVault encrypts the entire startup disk, so every file, app, and system setting is protected with a single password. Open System Settings > Privacy & Security > FileVault (on older macOS versions the path is System Preferences > Security & Privacy > FileVault), unlock the pane with your admin password, then click Turn On FileVault. You will be asked to choose a recovery method: either Allow my iCloud account to unlock my disk or Create a recovery key and do not use my iCloud account. After the Mac restarts, encryption runs in the background. Once it finishes, the Mac will require the login password or recovery key at every startup. FileVault covers the whole drive, not individual documents, so it is the best fit if you want automatic protection for everything on your Mac. Apple’s FileVault support page details the recovery options and setup steps.

What Happens If You Lose The Password?

With Preview, Word, and Disk Utility, there is no recovery option — a forgotten password means the data is gone. Apple’s own guidance is blunt about this: no backdoor, no customer-service reset. FileVault is the single exception because it lets you tie recovery to your iCloud account or a manually saved recovery key. For every other method, write down the password and store it somewhere secure (a password manager is the safest bet) before you apply encryption. That one step separates a protected file from a permanently locked one.