Oracle 12c SYSTEM user locked out

We have a development Oracle 12c database and the SYSTEM user account is locked out for one of the SID’s (works fine with another SID). When I try to do a conn SID / as sysdba it keeps connecting me to another SID that’s idle. So I cannot even get to the SID that has the locked account.

Any ideas on how to connect to the SID that has the locked SYSTEM account so I can unlock and reset the password?

Thanks.

Ok, figured it out with the comments from my original question. Steps I used to connect to the correct instance and get the account unlocked and password reset.

1. Connect to the correct SID/instance off the top. Example:

   c:sqlplus SYSTEM/<Password>@<service name> –> this can be found in the tnsnames.ora file

2. I then verified I was in the correct instance:

   SQL>select instance_name, status from v$instance;

3. From there I was able to unlock the user and reset their password:

   SQL>alter user <USERNAME> account UNLOCK;

   SQL>alter user <USERNAME> identified by <PASSWORD>;

My problem intially was that I was just trying to connect using sqlplus / as sysdba and it wasn’t putting me in the correct instance.

Hopefully this will be helpful to other Oracle devs and rookie DBA’s (I’m a rookie in this since we have a dev instance for some client work and it rarely gets touched).