Encrypt External Drive

The encrypt option in the Finder's contextual menu is still there:

How is the drive formatted currently? It must be formatted OS X Extended (journaled) or APFS in order for the Finder/System to be able to encrypt it.

When you prepare a new APFS format, you have these choices: APFS or APFS-Encrypted chosen in Disk Utility at the time the drive is formatted.

Although the drive in question is not a start up. Things must of changed. It's SoftRaid.

Since SoftRaid controls the underlying structure of the drive, it probably can't be encrypted.

I wondered about RAID, but my AppleRAID drives could be encrypted.

Formatted a USB and it shows the encryption. Odd though the other drives are formatted the same way.

Did you look at the partition map scheme? It must be GUID, but I think it has to be that for APFS, also.

Yes, thank you. And there was also an option to right click on an existing drive to encrypt. Seems it gone for some reason.

It is still available on all of my external drives. As I already mentioned, the only reason I know that the drive cannot be encrypted, usually a partition table reason.

Does it have an OS installed on it? That may be the reason. Of all of my drives, only the startup drive does not have the option to Encrypt.

I just use AppleRAID. Searching the web doesn't indicate any benefit to using SoftRAID over AppleRAID, and you can encrypt AppleRAID.

So, I wonder if I changed to AppleRAID if I would have to start over?

Yes, you would.

Use the drive Erase in Disk Utility to encrypt a drive. You cannot encrypt an external drive on the fly while in use. Please see Encrypt and protect a storage device with a password in Disk Utility.