How to Password Protect a Folder on Mac

Steps use macOS 14 and later names. Menu wording can differ slightly between versions.

The built-in way: an encrypted disk image

A disk image is a file that behaves like a small drive. When you encrypt it, macOS asks for the password each time you open it. The folder's contents are AES-encrypted inside the file.

1. Keep a safe copy first

   Copy the folder somewhere temporary. You will delete the original only after you have opened the encrypted version and checked it.

2. Open Disk Utility

   Press ⌘Space, type Disk Utility and press Return. It also lives in Applications > Utilities.

3. Start the image

   Choose File > New Image > Image from Folder…, select your folder and click Choose.

4. Set the encryption

   Name the image and choose where to save it. In the Encryption menu pick 256-bit AES encryption. Enter a password twice and click Choose.

5. Pick a format

   For a folder you will not change, read-only or compressed is fine. If you want to keep adding files, use the blank-image method below instead.

6. Save

   Click Save. Disk Utility writes YourFolder.dmg.

7. Test it

   Double-click the .dmg and enter the password. Do not tick "Remember password in my keychain", or the image will open without asking.

8. Remove the original

   Delete the plain folder and empty the Trash. Read the Time Machine warning below before you rely on this.

If you want to keep adding files

Choose File > New Image > Blank Image… instead. Set a size, pick APFS as the format, choose 256-bit AES encryption, and set the image format to sparse bundle disk image, which grows as you add files. Open it, drag files in, and eject it when you finish.

The Terminal version

hdiutil create -encryption AES-256 -srcfolder ~/Documents/Private -format UDZO ~/Desktop/Private.dmg

Other built-in options and where each one stops

Without Disk Utility

If you would rather not use Disk Utility, these also work, each for a narrower job:

• Terminal: the hdiutil command above makes the same encrypted image with no windows.
• A locked note for text and some images (see the table).
• An encrypted PDF from Preview for single documents.
• An app such as Cryptomator (open source) or, when it is released, a vault app with its own lock.

Where the built-in way falls short

• Old backups keep the plain folder. If Time Machine backed up the folder before you encrypted it, those backups still hold it unencrypted.
• A mounted image is an open image. The password is only checked when you open it. If you forget to eject, it stays readable.
• The file is visible. A .dmg named Private.dmg tells anyone that something is hidden.
• Mac may keep traces. Previews and recent-file lists can remember file names after you eject.
• No recovery. Forget the password and the data is gone. Apple cannot get it back.

The one-drag way with Hidden Folder

How it compares with each built-in option is on the Disk Utility comparison and the FileVault comparison.