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

oracle-10gsysdba

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.

Best Answer

Are you connecting as

 sys as sysdba

or

 / as sysdba

?

If you are using the first option, is it prompting you for a password, and are you entering the password for the user? Did you create a local Windows user account as the user, not the user id used to install the software? Oracle recommends a user with administrators group install the software, and a local Windows user be defined for the sys and system accounts.