How to Encrypt a USB Flash Drive in macOS Mojave

In macOS Mojave, you can choose to encrypt and decrypt disks on the fly right from the desktop. Using this convenient Finder option, we're going to show you how to encrypt a USB flash drive (or "thumb drive"), which is useful if you're traveling light and want to take sensitive data with you for use on another Mac.

Finder uses XTS-AES encryption, the same encryption that FileVault 2 uses to prevent access to data on a Mac's startup disk without a password. Note that the following method is only compatible with Macs – you won't be able to access data on the encrypted drive using a Windows machine.

If this is a requirement, you'll need to use a third-party encryption solution like VeraCrypt. With that in mind, here's how to securely encrypt your USB flash drive.


Attach the USB flash drive to your Mac and locate its disk icon on your desktop, in a Finder window, or in the Finder sidebar, then right-click (or Ctrl-click) it and select Encrypt "[USB stick name]"... from the contextual menu.

(Note that if you don't see the Encrypt option in the dropdown menu, your USB flash drive hasn't been formatted with a GUID partition map. To resolve this, you'll need to erase and encrypt the USB drive in Disk Utility – before that though, copy any data on the drive to another location for temporary safekeeping.)


When you select Encrypt, Finder will prompt you to create a password, which you'll need to enter the next time you attach the USB flash drive to a Mac. (Don't forget this, otherwise you'll lose access to any data stored on the USB drive!) Once you've chosen a password, verify it, add a meaningful hint if desired, and click Encrypt Disk.

The encryption process depends on how much data you have on the USB flash drive, but you'll know it's completed when its disk icon disappears and re-mounts. You'll now be able to access the contents of the USB flash drive as usual, but if you physically detach it and re-attach it to your Mac you'll be prompted to enter the password.


Note that the prompt includes an option for macOS to remember this password in my keychain. Check the box, and whenever you attach the USB stick to your Mac again you won't be prompted to enter the password and you'll have automatic access to it, just like any other drive.


If you ever want to decrypt the USB flash drive in future, right-click (or Ctrl-click) its disk icon, select Decrypt "[USB stick name]" from the contextual menu, and enter the password to turn off encryption protection.

How to Encrypt a USB Flash Drive in Disk Utility

Before proceeding, make sure you've copied any data on the USB flash drive to a safe location, like your Mac's internal disk.
  1. Launch Disk Utility, located on your Mac in Applications/Utilities.

  2. In the Disk Utility toolbar, click the View button and select Show All Devices if it isn't already ticked.

  3. Select your USB flash drive in the sidebar by clicking its top-level device name (i.e. not the volume name that's listed beneath it).

  4. Click the Erase button in the toolbar.

  5. Give the USB flash drive a name.

  6. Next, click the Scheme dropdown menu and select GUID Partition Map. (It's important to do this first before the next step, otherwise you won't see the encryption option in the Format dropdown.)

  7. Now click the Format dropdown menu and select Mac OS Extended (Journaled, Encrypted).

  8. Click Erase.

  9. Enter your new password, enter it once more to verify, include a password hint if desired, then click Choose.

  10. Click Erase once again, and wait for your disk to be formatted and encrypted.
Once the process is complete, copy across your sensitive data to the blank USB flash drive, where it will be automatically encrypted and secured with a password.



Top Rated Comments

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8 months ago
Using Dark Mode for screenshots isn‘t a good choice for tutorials.

I‘m sorry!
Rating: 13 Votes
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8 months ago

Disagree. It’s an official feature in Mojave and one can still follow the exact same options despite it being in dark mode.

It’s not that the process is different. It’s that black text on a white background is easier to read. Heck, some of the text is grey on black; how in the world could that ever be seen as anything close to desirable for tutorials for the masses? With my vision I’m having difficulty reading it. Let what’s stood the test of time be displayed for the vast majority, and run dark mode on your own machine on your own time.
Rating: 6 Votes
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8 months ago

Using Dark Mode for screenshots isn‘t a good choice for tutorials.

I‘m sorry!


Disagree. It’s an official feature in Mojave and one can still follow the exact same options despite it being in dark mode.
Rating: 5 Votes
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8 months ago

Using Dark Mode for screenshots isn‘t a good choice for tutorials.

I‘m sorry!

Exactly why I came to comment. In a dark environment, with dark surroundings, I believe dark mode is awesome. In a bright context (mac rumors home page for example), its just terrible. MR editors take note!!
Rating: 3 Votes
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8 months ago

Is there a way to force this to back up to iCloud?
Thanks

I played around with it, and it looks like you can copy the entry from the login Keychain and paste it into the iCloud Keychain. But instead of keeping the drive name, it changes it to the UUID # of the drive.



I right clicked and copied it from login then right clicked and pasted in iCloud Keychain and it made the new entry you see here in the iCloud Keychain. Presumably this would sync along with everything else in the iCloud Keychain.

I have not tested if you delete this entry from login Keychain if this iCloud entry will unlock the drive.



Rating: 2 Votes
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16 weeks ago

Thank you,

There is no "scheme dropdown" option as it is possible to see on the image I uploaded above. :(



Make sure you have enables show all devices, then select the drive itself like in my photo and not one of the volumes below it.

Rating: 2 Votes
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8 months ago
Since I generally need to use my USB sticks on both Windows and Mac (plus occasionally Linux), what I do is create a Veracrypt image on an exFAT-formatted USB stick. I leave enough room for the Mac installer on there - you can make Veracrypt containers “portable” (self-contained) for Windows, but for Mac you need to have Veracrypt installed on the computer.

It’s surprising, but there are still occasions when a USB stick is easier and faster than working over the network.

BTW if you aren’t familiar with Veracrypt - it’s the maintained successor to the last audited version of TrueCrypt.
Rating: 1 Votes
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8 months ago

Yep... it works the same as the USB key in this article. Assuming the drive is already properly formatted, just right click and select encrypt.

The only caveat is that it depends on how full the disk is. Some room (although not much) must be made for the Core Storage headers, if the disk is formatted as HFS+. APFS doesn't need to make extra room, though.
Rating: 1 Votes
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8 months ago
Dark mode is beautiful! One thing I like about Mac OS is the ease of encrypting personal data.
Rating: 1 Votes
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8 months ago

Can you encrypt a spinning external hard drive, after it is full of data?

Yep... it works the same as the USB key in this article. Assuming the drive is already properly formatted, just right click and select encrypt.
Rating: 1 Votes
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