ORA-01031: insufficient privileges while connecting with sys as sysdba

Question

I installed Oracle database 10g as an administrator on a windows 10 machine, it worked fine, but when i try to connect sys as sysdba it gives me the error:

ORA-01031: insufficient privileges

I checked sqlnet.ora file and if SQLNET.AUTHENTICATION_SERVICES is NTS and it is:

SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

I added the user to the ORA_DBA group and i checked with:

c:\Oracle>echo %username%

and

c:\Oracle>NET LOCALGROUP ORA_DBA

and the user is in the group.

I don't know what else i should do, anything will be helpful.

Answer 1

Would you mind to share what you exactly did? Please, copy/paste your command prompt session; something like this:

C:\>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Pet Pro 15 22:13:41 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production

SQL>

or

C:\>sqlplus sys@xe as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Pet Pro 15 22:18:59 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Enter password:

Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production

SQL>

A possible culprit: have you modified TNSNAMES.ORA file and added some databases in there? If so, try to specify database name (as I did in my second example).