Once encryption has started, most drives finish encryption normally. On some occasions, however, the encryption process may stop on its own. The cause is generally a problem with the drive being encrypted.
If the system being encrypted loses power during the process, encryption will automatically stop. Depending on whether or not you were using the Safe Mode option (--safe-mode), you have two options:
The best practice for a drive where encryption stopped automatically is to decrypt the partially encrypted drive, check it for problems, then start encryption again.
Caution: Be sure to fully decrypt any drive on which encryption was started before checking it for problems.
Decrypt the drive that was partially encrypted using the following: