How do I encrypt an external drive with FileVault 2 in OSX Yosemite Ok, so according to https://www.apple.com/osx/what-is/security/ I should be able to encrypt ANY external drive..."with ease" using FileVault 2.

I have a brand new (empty) 2TB Fantom Drive model: GFP2000EU3 (Hitachi Drive)

Disk Utility:


I tried to erase and format the drive to Mac OS Extended (Journaled, Encrypted) Returned Error: "A GUID Partition Table (GPT) partitioning scheme is required."
Selected Logical Volume in left list, then went to Partition tab, clicked on dropdown, showing "Current," changed it to 1 partition, clicked Options button, then selected GUID Partition Table radio button > clicked OK, then Apply on main window. No errors came during this step.
Tried step 1 again, different error message: "Unable to create a new Core Storage logical volume group."


Finder:


Attempted ctrl+click>Encrypt *Drive Name* drive icon on my desktop, same error: "Unable to create a new Core Storage logical volume group."


I also tried a disk repair before trying again. Then tried all these steps again in Recovery Mode (command+R during startup), then tried under Safe Mode (holding shift at startup), and then under another user account. All come back with same error: "Unable to create a new Core Storage logical volume group."

Update 1:: I was able to successfully encrypt a 8gb Sandisk thumb drive. Still need to take care of the 2TB.

$diskutil list

/dev/disk3
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:      GUID_partition_scheme                        *2.0 TB     disk3
1:                        EFI EFI                     209.7 MB   disk3s1
2:                  Apple_HFS MyDrive                 2.0 TB     disk3s2


After chats with Apple tier 1 &amp; Senior Support, they've ran CaptureData and a Systems Engineer is looking into this, may take a day or two. They said they have little to no documentation yet on my problem. Seems unlikely that I'm the only one...

Update 2: I received repair authorization from Fantom and overnighted the drive (at my expense). After inspection I received this message: "We've completed diagnostics on your drive and regret to inform you that the hard disk inside the case has failed. As such, the damage is now beyond our ability to repair- we will replace the disk drive mechanism and return the repaired unit."

I find this interesting, because I may not have found out about this problem until after I loaded critical data on the drive. I was able to format the drive and copy to and from the drive without issue...encrypting the drive exposed the problem. I still need to confirm that the "repaired unit" will encrypt as expected, hopefully I will receive that back soon.



Final update: after receiving the new drive, everything encrypted as expected. My advice is to try to encrypt every drive when you first get it, as a failure may detect some glitches that you'd want to see sooner rather than later...
I understand that you're running into issues, so this is going to be more for others looking for info on this topic. Encrypting non-boot volumes should be a relatively easy process in OS X 10.8.x and later.

To encrypt a non-boot volume:


Right-click on the volume you want to encrypt
Select the Encrypt… command





When prompted, enter a password and (optionally) a password hint.




The drive will momentarily disappear from the desktop (to initialize the encryption) then re-appear.