ORA-40365: The SYS user cannot be locked while the password file is in its current format.

CMD > orapwd file=$ORACLE_HOME/database/pwd$ORACLE_SID.ora format=12.2

CMD > orapwd describe file=pwd$ORACLE_SID.ora

Password file Description : format=12  

CMD > sqlplus / as sysdba

SQL> show user

USER is "SYS"

SQL> alter user sys account lock;

User altered.

SQL>  select username,lock_date from dba_users where username='SYS’:

USERNAME     LOCK_DATE

-------------------- ------------------

SYS     25-JAN-18

SQL> select username,lock_date from v$pwfile_users;

USERNAME     LOCK_DATE

-------------------- ------------------
SYS     25-JAN-18
SYSDG
SYSBACKUP
SYSKM