The following is formatted as error number -> error meaning.
0 No error, or successful operation.
1 FileVault is Off.
2 FileVault appears to be On but Busy.
11 Authentication error.
12 Parameter error.
13 Unknown command error.
14 Bad command error.
15 Bad input error.
16 Legacy FileVault error.
17 Added users failed error.
18 Unexpected keychain found error.
19 Keychain error. This usually means the FileVaultMaster
keychain could not be moved or replaced.
20 Deferred configuration setup missing or error.
21 Enable failed (Keychain) error.
22 Enable failed (CoreStorage) error.
23 Enable failed (DiskManager) error.
24 Already enabled error.
25 Unable to remove user or disable FileVault.
26 Unable to change recovery key.
27 Unable to remove recovery key.
28 FileVault is either off, busy, or the volume is
locked.
29 Did not find FileVault information at the specified
location.
30 Unable to add user to FileVault because user record
could not be found.
31 Unable to enable FileVault due to management settings.
32 FileVault is already active.
33 Command option is unsupported on this file system.
34 An option or parameter is not supported for APFS vol-
umes.
35 An error occurred during FileVault disablement.
99 Internal error.