Encrypted (FV2) startup > SD Clone?
 

Hi guys
I've searched the forum and the wider internet but I can't seem to find a definitive answer.

I have a 2017 MBP running High Sierra at the mo (may update to Mojave soon).

My SSD in the MBP is encrypted with FileVault under High Sierra.
I wish to make a bootable clone of my MBP startup disk to keep at a friend's house. It is therefore imperative that the external HDD that I intend to clone to is also encrypted after SD! has finished duplicating.

I can't find how to do this, or any reference to FileVault. I presume that as the startup disk is unlocked in order to use the Mac, so the clone would be unencrypted?

Do I need to reformat the external HDD and enable encryption in the Disk Utility first? Also, given that the onboard SSD is AFPS, what format should I use for the external USB-C hard disk?

Grateful for any advice.
Thanks
Paul

Format the external drive as APFS encrypted, then Smart Update to it. Should work fine.