use filevault to encrypt external drive?

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use filevault to encrypt external drive?

I would like to encrypt an external USB drive. The instructions on this page, https://support.apple.com/guide/mac-help/encrypt-disks-memory-cards-protect-mac-mh40593/mac

say:

In the Finder on your Mac, open a window, then Control-click the item you want to encrypt in the sidebar.
Choose Encrypt [item name] from the shortcut menu.
Create a password for the disk and click Encrypt Disk.
Important: Be sure to record and keep this password in a safe place. You cannot access the data on the encrypted disk without it.
It may take some time to encrypt, depending on how much information is stored on your Mac. However, you can use your Mac as usual while the disk is being encrypted.

BUT, doing this does not work - there is no "Encrypt" option when I control-click on the external USB drive, as the screen capture shows.

"Encrypt" is not available under the "Quick Actions" or "Services" menu, either.

So, how can the "Encrypt" option be activated? Does the system disk need to be encrypted before an external drive-in be? Does FileVault2 need to be turned on in System Preferences? (I tried turning on FileVault in System Preferences, then control-clicking, but that didn't make any difference the option to "Encrypt" did not appear, but I may be doing something incorrectly?)

I'm using macOS 10.14.5 on a 27" iMac 5K

Thanks.

iMac Line (2012 and Later)

Posted on Jun 15, 2019 10:28 AM

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Answer 1

Top-ranking reply

BobTheFisherman

Level 10

85,117 points

Jun 16, 2019 3:21 PM in response to E. Kennedy

Encrypt and protect a disk with a password using Disk Utility on Mac - Apple Support

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Answer 2

Barney-15E

Level 10

122,210 points

Jun 18, 2019 6:41 AM in response to E. Kennedy

You have to "Show All Devices" from the View popup menu above the volume list.

Then, select the actual device and not the volume.

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Answer 3

Barney-15E

Level 10

122,210 points

Jun 16, 2019 4:18 PM in response to E. Kennedy

To answer your questions, it is a 4GB external USB thumb drive in the MacOS Extended (Journaled) format and it is not used for TimeMachine backups.

Is it GUID partition table (GPT)? It must be for the OS to encrypt it.

It may have been possible for you to format the volume as Mac OS Extended but not GUID.

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Answer 4

Barney-15E

Level 10

122,210 points

Jun 16, 2019 7:58 PM in response to E. Kennedy

Look at the disk information in Disk Utility. If the drive is not GUID with the volume Mac OS Extended, then you cannot encrypt it. MBR would be the most likely possibility for the partition table.

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Answer 5

Tesserax

Level 10

158,058 points

Jun 15, 2019 10:39 AM in response to E. Kennedy

Per chance does this external drive being used for Time Machine backups? If so, even though it is formatted as 'Mac OS Extended (Journaled)' the 'Encrypt' option will not appear on the pop-up menu.

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Answer 6

E. Kennedy Author

Level 2

226 points

Jun 16, 2019 3:17 PM in response to BobTheFisherman

Thanks, BobTheFisherman and Tesserax for your replies.

To answer your questions, it is a 4GB external USB thumb drive in the MacOS Extended (Journaled) format and it is not used for TimeMachine backups.

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Answer 7

E. Kennedy Author

Level 2

226 points

Jun 16, 2019 4:20 PM in response to BobTheFisherman

Thanks for your reply and the info, but is the encryption with Disk Utility as strong as the encryption with FileVault ( I think with FileVault it's AES-128)?

And, also, if you know or have any idea, why is the "Encrypt (disk name)" option NOT available with Control-Click as the Apple Support web page says it will be?

Thanks.

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Answer 8

E. Kennedy Author

Level 2

226 points

Jun 16, 2019 4:28 PM in response to Barney-15E

Hi, Barney-15E, thanks for the reply but, to answer your question, I have no idea if it is GUID. I used Disk Utility to erase everything on the external thumb drive and reformat it to macOS Extended (Journaled) and don't recall if GUID was an available option when I did that.

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Answer 9

E. Kennedy Author

Level 2

226 points

Jun 17, 2019 12:34 PM in response to Barney-15E

Thanks for your reply, Barney-15E.

I did not see anything in Disk Utility that indicated that the external USB thumb drive is GUID. But, I also checked the internal HD where all the system files and OS are located- an APFS formatted volume, not macOS Extended (Journaled) format - and Disk Utility did not show anything indicating that disk was GUID, either. Also, when I Control-Click on the internal HD, the option to Encrypt did not appear in the resulting menu.

Must FileVault be turned on in the System Preferences in order to encrypt the internal HD as well as any other external HD or USB drive? And, can FileVault be turned on without encrypting the internal HD but only an external USB drive? I do not have FileVault turned on because I do not wish to encrypt my entire internal HD.

Thanks, again.

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Answer 10

E. Kennedy Author

Level 2

226 points

Jun 26, 2019 12:32 PM in response to Barney-15E

Thanks, Barney-15E.

I checked the disk again with DiskUtility and found that it is NOT a GUID partition map, but a Master Boot Record partition map. I also re-checked the internal HD and my TimeMachine external HD and they are both GUID, but neither of those has an "Encrypt" option available using Control+Click pop-up menu. Has the "Encrypt"option been discontinued in macOS 10.14.5 or is there another explanation why this option does not appear even though the Apple Support article that was cited earlier states that it can be used?

Thanks, again.

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Answer 11

Jun 15, 2019 10:30 AM in response to E. Kennedy

What format is the external drive?

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Answer 12

Barney-15E

Level 10

122,210 points

Jun 26, 2019 2:09 PM in response to E. Kennedy

Your Startup drive must be encrypted through FileVault.

Time Machine may be required to encrypt via the Time Machine system preference, but I'm not sure about that.

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use filevault to encrypt external drive?

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