Cannot change APFS encryption password I have a clean install of macOS High Sierra with APFS Encrypted file partition. 
During install I checked the "decrypt at login" option, but each have a different password. I now want to change my APFS password but I haven't been abled to:


"change password" is greyed out in the Disk Utility for my APFS volume.
diskutil apfs changePassphrase ...  returned an error saying it can't do it. 


Any idea how I can do that? 

P.S. I also have FileVault turned on, with the same password as my login (so different from the APFS Encryption).
You need to list your disks to find the APFS volume disk where you want to change the password:

sudo diskutil apfs list


Now find the UUID of the cryptographic Disk User:

sudo diskutil apfs listUsers &lt;your APFS volume, like: disk1s1&gt;


Finally you can change the APFS volume password:

sudo diskutil apfs changePassphrase &lt;your APFS volume, like: disk1s1&gt; -user &lt;the Disk User cryptographic UUID, like: 12345678-1234-1234-1234567890AB&gt;