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?


  • Sorry. This is on a Windows system. When I do connect as 'sqlplus / as sysdba' it default logs me into the other instance. I'll look at trying to force the environment to push me to the other instance and see if that works.
    – Valien
    Commented Aug 7, 2014 at 17:39
  • 1
    Is this a pluggable database ? If not, you just need to set your environment correct. There's no "default" SID, there often is a chaos of environment variables and related stuff, but as stated, in a chaos way. Often the first database installed, but not necessarily. So, question : how do you set your environment ?
    – tvCa
    Commented Jan 26, 2015 at 13:15

1 Answer 1


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).

  • 2
    set ORACLE_SID=<fancy instance> then sqlplus / as sysdba, would do the job as well
    – Munchi
    Commented Aug 11, 2014 at 12:42

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