ERROR: ORA-01031: insufficient privileges

Question

After installing Oracle and opening Command Prompt, I typed in sqlplus "/as sysdba" and got an error message ERROR: ORA-01031: insufficient privileges and then it asks me to enter the user-name. I'm using my own personal computer and although the name given after C:\Users\ is not called "Administrator", it's my username when I used to log in to this computer and since I'm the only one using the computer I'm assuming it's the same as "Administrator" and when I opened account settings it says administrator under my account name.

Microsoft Windows [Version 10.0.17134.228]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\Users\linus>sqlplus "/as sysdba"

SQL*Plus: Release 11.2.0.1.0 Production on Mon Aug 20 10:56:53 2018

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

ERROR:
ORA-01031: insufficient privileges


Enter user-name:

What might be the cause of this and what can I do to solve it? Thanks!

Answer 1

since I'm the only one using the computer I'm assuming it's the same as "Administrator"

That's not enough to be an Administrator.

Make sure that your user belongs to ORA_DBA OR ORA_<%ORACLE_SID%>_DBA OS group on Windows.

As well check the value set for SQLNET.AUTHENTICATION_SERVICES parameter on sqlnet.ora(%ORACLE_HOME%\network\admin) file. NTS should be included in the value.

SQLNET.AUTHENTICATION_SERVICES = (NTS)