Installed Oracle 18c XE approx 9/2019 on dan-PC-i7-QUAD.
sqlplus USER: / AS sysdba
Password like main but capital letter on 2nd to last letter.
These might work (originally from another installation):
ALTER SESSION SET "_ORACLE_SCRIPT"=TRUE; CREATE USER dwheele IDENTIFIED BY password; GRANT DBA TO dwheele; CREATE USER dcadmin IDENTIFIED BY dcadmin;