Is it possible to encrypt a hard drive that is dual booting ubuntu using rEFInd? I recently installed ubuntu on my macbook pro. I am using rEFInd to dual boot ubuntu. Following the installation, I tried to encrypt my Macintosh HD partition by first converting the disk to core storage. I received the following error message:

Error: -69730: Unable to create boot loader partition due to the specifics of your partition map layout

I was using FileVault for whole disk encryption before partitioning my hard drive in order to install Ubuntu. Is there any way to correct this error, or another method to encrypt my hard drive?

I am dual booting Ubuntu 16.04 on my 13 inch Macbook Pro from mid 2014 running El Capitan. This is what my partition lay-out looks like:
If you encrypt the OS X partition only.