Encrypting USB Flash Drives

If you use USB flash memory drives, also known as thumb drives or jump drives, you can encrypt them to make sure no one else can access your data if they get a hold of your drive. This is a system function in macOS Sierra that can be accessed in the context menu for that drive. Since these drives are easy to lose, it can be a good idea to encrypt them as standard practice.

Comments: 15 Responses to “Encrypting USB Flash Drives”

    Mr. Luigi
    2 years ago

    Hi Gary, Could I use this same procedure to encrypt my “always connected” backup harddrives? I ask because I’ve always worried that if someone broke into my house and took my very portable backup harddrives, they would have access to all the content on my computers. Love your site. Proud Partreon supporter.

    2 years ago

    Luigi: Yes, but you should use the Time Machine built-in encryption option. Same result, I believe, but done properly. See https://support.apple.com/kb/PH25539

    Dot
    2 years ago

    Thanks! I’m always learning new things from you. I use encrypted DMG files to store sensitive information on my MacBook Pro. They are then encrypted wherever I put them, on a backup drive, on a flash drive, or on another family computer. But perhaps encrypting the flash drive is more secure?

    2 years ago

    Dot: I don’t see how they are more or less secure — both are encrypted data. Doing the whole drive makes it easy to add/remove/modify the files since you don’t have to open and close the DMG. But DMGs are useful to encrypt data on a larger drive that is unencrypted.

    Ann
    2 years ago

    Once a drive is encrypted and in use, can you change the encryption password? can you unencrypted the drive and then encrypt it again later with a different password? if you do lose the password (accepting that files are unrecoverable) can you reformat the drive (not having the encryption password) so that you can use it again as a blank drive?

    2 years ago

    Ann: Yes. You can unencrypted the drive the same way, and then encrypt it again with a different key/password. You can of course erase the drive without the password and use it as a blank drive. I encourage you to play around with this — try it all with a drive and see how it works.

    Tom
    2 years ago

    Gary, big fan, love your stuff. I have to move USB drives between Windows and Mac. What happens when I take the Mac encrypted drive to Windows? Can you make a video showing the best way to format USB drives for use on both platforms? Thanks!

    2 years ago

    Tom: You can’t do it. Windows can’t read Mac-formatted drives, let alone Mac-formatted drives that are encrypted. To format for both platforms, just use ExFAT or FAT in Disk Utility. But it wouldn’t be encrypted. A better solution in 2017 is to simply use a cross-platform cloud service like DropBox.

    Patti Rogers
    2 years ago

    Gary,
    When I just tried to follow the instructions…I got a pop up saying A GUID Partition Table (GPT) partitioning scheme is required.
    Not sure how to proceed. I’m using Sierra 10.12.6 on my MacBook Pro which is 5 years old. Any suggestions. Thanks for what you do.

    2 years ago

    Patti: Sounds like the drive is not formatted with Macintosh Extended and GUID. You can reformat (erase) the drive with this using Disk Utility.

    Patti Rogers
    2 years ago

    Thanks Gary…will do it.

    Barry
    2 years ago

    In Sierra, when encrypting a USB flash drive, we are not given the choice of 128-bit or 256-bit encryption as we are when creating a new encrypted blank image using Disk Utility. Do you know which level of encryption is being used? Thanks.

    2 years ago

    Barry: My guess would be 256. But if it is important to you, then why not use Disk Utility and be sure?

    Barry
    2 years ago

    Gary – Even when using Disk Utility to encrypt a USB flash drive, we are not given the choice – it’s similar to right-clicking on the flash drive and choosing Encrypt. Only when creating a new encrypted blank image in Disk Utility is the choice given. Apple is making the choice for us when it comes to flash drives, but not telling us what that choice is.

    2 years ago

    Barry: Looks like with High Sierra things are in flux. I don’t even see this option at the moment.

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