ORA-01017 Invalid Username/Password in SQL Developer I installed Oracle 18c XE and SQL Developer 18.4, both are the latest.

Logged in with SYSTEM and created a user vbk in SQL Developer.

I see the user running select * from dba_users, but when I try to connect in SQL Developer, it says  

ORA-01017 Invalid Username/Password


I tried to reset the password with SYSTEM user:

ALTER USER vbk IDENTIFIED BY xxx;


and I get

ORA-01918: user 'VBK' does not exist 


I see that in the message the user name is upper case, even though the user was created with lower case.

How to connect with the user?
As explained in this answer on SO, if you create a user (or any other identifier) in lowercase, you will have to always quote it when referencing, because by default Oracle (and other SQL databases, except may be Postgres) will convert unquoted identifiers to uppercase.

connect "vbk"/password


or

ALTER USER "vbk" IDENTIFIED BY xxx;