While it was working fine, I had to stop the server once. When trying to start Oracle using a script we have, I got the following error:

SQL> Connected to an idle instance.
SQL> ORA-01081: cannot start already-running ORACLE - shut it down first
SQL> Disconnected

Also when trying to start SQL Plus manually AS SYSDBA I get:

ORA-12162: TNS:net service name is incorrectly specified

Using SQL Plus with other users, I get:

ORA-12537: TNS:connection closed

Any help appreciated ...

  • Have you tried restarting the machine itself? I'm primarily a Windows guy - hence the "restart" advice.
    – Hannah Vernon
    Commented Aug 8, 2013 at 1:48
  • Double check ORACLE_HOME and ORACLE_SID environment variables. Also look what Oracle processes are running and what messages are in alert log. I'm speaking from Linux experience. Commented Aug 8, 2013 at 5:15

3 Answers 3

  • 1st check contents of the ORACLE_SID and ORACLE_HOME variables. Even a trailing slash at the ORACLE_HOME path makes difference

  • Locate files "alert_${ORACLE_SID}.log" and "listener.log", there you will find more information


Note that if you are trying to run a script using crontab, all Oracle specific environment variables need to be set inside the script. It will not take values from .profile/.bash_profile files.

Looks like the ORACLE_SID and ORACLE_HOME variables are not set


Try the following command:

startup force
  • 1
    Typically you should add more details to your answer. Even though you may be correct, further details will help the OP and future visitors to understand why.
    – Hannah Vernon
    Commented Aug 13, 2013 at 1:09

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